PSEB Notes

This PSEB 10th Class Science Notes Chapter 5 Periodic Classification of Elements will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 5 Periodic Classification of Elements

→ The arrangement of elements in such a manner that the elements having similar elements are grouped together whereas the elements having different properties are separated is called classification of elements.

→ According to Dobereiner Triads, the elements were arranged in order of increasing atomic masses and grouped into three elements such, that the elements had similar properties such that the atomic mass of the middle element was average of the other two elements.

→ The classification done by Dobereiner on the basis of triads was not applicable to classify all the elements.

→ In 1866, on the basis of the law of octaves, Newland classified elements till calcium whose atomic mass is 40.

→ Russian chemist, Mendeleev discovered periodic law which is famous by the name Mendeleev’s periodic law which states that the physical and chemical properties of the elements are the periodic functions of their atomic masses.

→ Mendeleev’s periodic table was arranged into periods and groups.

→ Horizontal rows are called periods and vertical columns are called groups.

→ In the main periodic table, Mendeleev left the places for those elements which were not discovered till then.

→ According to Modern Periodic Law, the physical and chemical properties of elements are the periodic functions of their atomic number.

→ In modern periodic tables, elements are arranged in 18 vertical columns known as groups and 7 horizontal rows known as periods.

→ Elements of group zero/18 are known as noble gases.

→ The repetition of the similar properties of elements placed in a group and separated by definite gaps of atomic number is called periodicity.

→ There are also some defects in the long form of the periodic table.

→ Scandium, gallium, germanium, etc., were discovered after Mendeleev’s periodic table. In 1913, Henry Moseley said that in comparison to the atomic mass of elements, atomic number is a more fundamental property.

→ By arranging the elements in ascending order of atomic number, their properties can be estimated more precisely.

→ By atomic size, we can find the atomic radius.

→ The atomic radius of Hydrogen is 37 pm (Picometer, 1 pm = HP12 m).

→ Atomic radius decreases on moving left to right along a period.

→ By metalloids properties of metal and non-metals are differentiated. Metalloids are-Boron, Silicon, Germanium,

→ Arsenic, Antimony, Tellurium, and Polonium. Oxides of metals are basic and oxides of non-metals are acidic.

→ The minimum energy required to remove an electron from the valence shell of an isolated gaseous atom is known as ionization energy.

→ The energy released when an electron enters the outermost shell of a neutral gaseous atom is known as electron affinity.

→ As we move down in a group, metallic properties increases.

→ On moving down in a group from top to bottom ionization energy decreases.

→ Periodic Table: This is a table in which we classify the elements in a specific order.

→ Newlands’ Law of Octaves: It states that when the elements are arranged in the ascending order of their increasing atomic weights, every eighth element has properties similar to the first element like the notes of an octave of music.

→ Dobereiner’s triads: It is a group of three elements having similar chemical properties in which the atomic weight of the middle element is the average of the other two elements.

→ Periodic classification is the systematic study of the properties of the elements.

→ Periodic Table: It is a table or chart in which the various elements are arranged in such a manner that elements having similar properties fall in the same vertical column whereas dissimilar elements are separated.

→ Mendeleev’s Periodic Table: The table of elements made by Mendeleev is known as Mendeleev’s Periodic Table, which is based on atomic mass.

→ Modern Periodic Table: The table which was made after the modification of Mendeleev’s Periodic Table, is known as Modern Periodic Table or extended form of the periodic table. It is based on atomic number.

→ Mendeleev’s Periodic Law: Physical and chemical properties of elements are the periodic functions of their atomic masses.

→ Periods: Horizontal rows in a periodic table are known as periods.

→ Groups: Vertical columns of the periodic table are known as groups.

→ Modern Periodic Law: The physical and chemical properties of elements are the periodic function of their atomic number.

→ Periodicity: Repetition of characteristics of elements in a group is known as periodicity.

→ Atomic Radius: The distance from the nucleus of an atom to its outer shell is known as atomic radius.

→ Valence Electrons: The number of electrons in the valence shell of an atom is known as valence electrons.

→ Ionization Potential: The ionization potential of an element is the minimum energy required to separate an electron from the outermost shell of a gaseous atom of that element.

→ Electron Affinity: The energy released when an electron enters the outermost shell of a neutral gaseous atom is known as electron affinity.

→ Valency is the combining capacity of the element and is equal to either the number of valence electrons or eight minus the number of valence electrons.

→ Lanthanides: Fourteen elements starting from lanthanum having atomic numbers 58 to 71 are called lanthanides.

→ Actinides: Fourteen elements starting from actinium having atomic numbers 90 to 103 are called actinides.

→ Metalloids: Elements that behave both as metals and non-metals are called metalloids.

→ Periodic Properties: These are the properties of an element that are related to the electronic configuration of its atom and change periodically down a group and along a period.

→ Atomic Size: In a period, with the increase of atomic number, there is a decrease in atomic radius. By going from left to right, the atomic number increases, and the size of the atom decreases. This is called atomic size.

→ Representative Elements: The elements of sub-group A are known as representative elements.

→ Need for classification: Elements are grouped based upon similarities in their properties in order to simply and systematically study of the properties of the elements.

Modern Periodic Table:

This PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 4 Carbon and its Compounds

→ In our daily life, the maximum things used by us are compounds of carbon.

→ All living species involve carbon.

→ A very small quantity of carbon present in nature is used by us.

→ Most of the carbon compounds are not good conductors of electricity.

→ The bonding of carbon compounds does not produce any ions.

→ The atomic number of carbon is 6. It has four electrons in its outermost shell.

→ It can gain four electrons forming C^4- anion or it can lose four electrons forming C⁴⁺ cation.

→ Hydrogen requires one or more than one electron. The shared pair of electrons is said to constitute a single bond between two hydrogen atoms.

→ Chlorine forms a diatomic molecule.

→ Oxygen forms a double bond between two oxygen atoms.

→ In order to attain an octet, each nitrogen atom in a molecule of nitrogen contributes three electrons giving rise to three shared pairs of electrons.

→ Methane is a compound of carbon. It is the major component of bio-gas and compressed natural gas (CNG).

→ It is one of the simplest compounds of carbon.

→ Diamond and graphite are allotropes of carbon. They have the same chemical properties.

→ Fullerenes form another class of carbon allotropes which was first identified as C-60.

→ There are around 3 million carbon compounds in number.

→ The nature of a covalent bond enables carbon to form a very large number of compounds.

→ Carbon shows Catenation to the maximum extent.

→ The organic compounds having the presence of carbon-carbon single bonds only are termed saturated compounds.

→ The carbon-Carbon bond is very stable and strong.

→ Compounds of carbon are formed with oxygen, hydrogen, nitrogen, sulphur, chlorine, and some other elements.

→ Since carbon has a valency of four and is capable of bonding, it forms a large number of compounds.

→ The saturated compounds of carbon and hydrogen are methane, ethane, propane, butane, pentane, hexane.

→ The compounds with identical molecular formulas but different structures are called structural compounds.

→ In addition to straight and branched carbon chains, some compounds have carbon atoms arranged in the form of rings. For example, cyclohexane.

→ Saturated hydrocarbons are called ‘Alkanes’. Such unsaturated hydrocarbons which have one double bond are called ‘Alkenes’. Those having one triple bond are called Alkynes’.

→ All hydrocarbons burn in the presence of oxygen and release heat, light, and CO₂.

→ Saturated hydrocarbons generally produce clean flame on burning while unsaturated carbon compounds produce a yellow flame with a lot of black smoke.

→ Incomplete combustion produces a sooty flame.

→ A flame is produced when gaseous substances are burnt.

→ Coal and petroleum are fossil fuels that have been formed from biomass that has been subjected to various biological and geological processes.

→ Alcohol can be converted into carboxylic acids by complete oxidation.

→ Substances that are capable of adding oxygen to other substances are known as oxidizing agents.

→ Catalysts are substances that cause a reaction to occur or accelerate the rate without reacting and getting affected.

→ Ethanol is a liquid at room temperature. Ethanol is commonly called alcohol.

→ Consumption of small quantities of ethanol tends to slow metabolic processes and depress the central nervous system.

→ Consumption of methanol even in very small quantity can cause death. It can also cause blindness by affecting the optic nerve.

→ Methanol is mixed with ethanol to prevent its misuse. Dyes are added to colour the alcohol blue. This is called denatured alcohol.

→ Sugarcane juice can be used to prepare molasses which is fermented to give ethanol.

→ Ethnic acid is commonly called acetic acid. 3.4% solution of acetic acid in water is called vinegar.

→ Carbon: Carbon is an element that is of immense significance in its elemental and combined form. Placed in 14th group of periodic table with atomic number 6, mass number 12 and electronic configuration 4 it has electronic valency 2, 4 and is symbolised as \({ }_{6}^{12} \mathrm{C}\).

→ Carbon compounds: The compounds in which carbon is present are called carbon compounds. These are generally covalent. Ionic compounds of carbonates are not included in this.

→ Covalent bonds: The bond formed by sharing of electrons is known as a covalent bond.

→ Allotropy: The property of an element by virtue of which it can exist in two or more physical forms of the same chemical element, with the same chemical properties.

→ Hydrocarbons: The covalent compounds of hydrogen and carbon are called hydrocarbons.

→ Saturated hydrocarbons: The hydrocarbons with the same chemical formula C_nH_2n+2 are called alkane. These have a covalent bond between the members of the same category.

→ Isomerism: The compounds with the same molecular formula but different structural formulas are called isomers and the phenomenon is known as isomerism.

→ Unsaturated Hydrocarbons: The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated hydrocarbons.

→ Alkene: Generally a hydrocarbon with the chemical formula C_nH_2n is called alkene.

→ Alkyne: The carbon compound containing a triple bond between carbon atoms is called alkyne.

→ Catenation: The carbon atoms form bonds with other carbon atoms to form long-chained compounds. This property is known as catenation.

→ Allotropy: The phenomenon of the existence of two or more physical forms of the same chemical element, with the same chemical properties, is called allotropy.

→ Fullerenes: There are the allotropes of carbon having a football or bucky ball-like structure.

→ Addition reactions: These are the reactions in which some molecules get added to unsaturated Hydrocarbon like alkene/alkyne.

→ Substitution reactions: These are the reactions in which an atom or group of atoms from an organic compound is replaced by another atom or group.

→ Esterification: The reaction of a carboxylic acid with an alcohol to form an ester is called esterification.

→ Functional group: An atom or group of atoms that determines the chemical properties of an organic compound is called a functional group.

→ Fermentation: The process of conversion of complex organic compounds into simple organic compounds with the help of enzymes is known as fermentation.

→ Alcohol: The compound obtained by the replacement of a hydrogen atom of alkane by hydroxyl (-OH) functional group is called alcohol: Its general formula is C_nH_2n+1 OH.

→ Carboxylic acid: Carboxylic acids are those organic compounds that have (-COOH) as a functional group.

→ Homologous series: A series of organic compounds having the same functional group formula and possessing similar chemical properties are termed homologous series.

This PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 3 Metals and Non-metals

→ Iron, Copper, Aluminium, Magnesium, Sodium, Lead, Zinc, etc. Metals are easily available.

→ Metals have shining surfaces, called metallic luster.

→ Sodium metal can be cut by a knife.

→ Metals are usually hard and can be beaten into thin sheets and drawn into wires.

→ Gold is most ductile that is why from one gram of gold, a 2km long wire can be drawn.

→ Metals are good conductors of heat.

→ Malleability and ductility are two important properties of metals.

→ Lead and mercury are bad conductors whereas silver and copper are very good conductors.

→ Metals have sonorous properties.

→ Carbon, Sulphur, Iodine, Oxygen, Hydrogen etc. are non-metals.

→ Bromine is a non-metal which exists in liquid form.

→ Mercury exists in liquid form at room temperature.

→ Gallium and Cesium have a very low melting point, which melts even when placed on our palms.

→ Iodine is non-metal but is lustrous.

→ Lithium, Sodium, Potassium are alkali metals and are very soft, they can be cut with a knife.

→ Most of the non-metals produce acidic oxides when dissolved in water.

→ Magnesium burns in the air with dazzling white flame.

→ On heating copper, it changes to black coloured copper oxide.

→ Those metal oxides that react with acid as well as with bases and produce salt and water in both cases are called amphoteric oxides.

→ Gold and silver do not react with oxygen even on heating.

→ Aqua regia is a fresh mixture of concentrated HCl and Concentrated HNO3 in the ratio 3 : 1.

→ Aqua regia can dissolve in Gold and platinum.

→ Reactivity series is a list of metals in which metals are arranged in decreasing activity.

→ Noble gases have completely filled valence shells and thus are less reactive.

→ Helium, Neon, Argon are Noble gases.

→ Compounds formed by the transfer of electrons from metals to non-metals are called ionic or electrovalent compounds.

→ Ionic compounds are solid and hard. They have high melting and boiling point. They can conduct electricity.

→ Earth’s crust is the main source of metals.

→ The elements or compounds which occur naturally in the earth’s crust are called minerals.

→ Some of the minerals from which extraction of metals is easy and profitable are called ores.

→ Gold, silver, platinum, and copper are at the bottom of the reactivity series and are least reactive, and are found in a free state.

→ Zinc, Iron, lead are moderately reactive and are found in the form of oxide, sulphide, or carbonate in the Earth’s crust.

→ Sodium, Potassium, calcium, Magnesium, Aluminium, etc. are at the top of the reactivity series and are so reactive that they are never found in a free state in nature.

→ Ores are contaminated with impurities like soil, sand, etc. known as gangue.

→ If sulphide ores are heated in excess air, they convert to oxides. This is called roasting.

→ Carbonate ores are converted into oxides by heating them strongly in a limited supply of air. This is known as calcination.

→ The reaction of iron oxide with aluminium is called the thermit reaction.

→ Electrolytic refining is used to purify metals.

→ Silver articles become black after some time when exposed to air due to the formation of a coating of silver sulphide.

→ Copper gains a green coating of basic copper carbonate due to corrosion when left in air for a long time CuCO₃.Cu(OH)₂.

→ Iron acquires a brown coating called rust.

→ Corrosion is prevented by greasing, painting, galvanising, chrome plating, anodizing, etc.

→ The homogeneous mixture of two or more two metals is called an alloy.

→ Pure Gold, which is 24-carat gold, which is very soft.

→ For making ornaments silver or copper is mixed with gold.

→ Generally, 22-carat gold is used for making ornaments. If alloy contains one of its constituents as mercury (Hg) it is called amalgam.

→ Alloy Bronze is a bad conductor of electricity.

→ Ductility: It is a property of metals by virtue of which long wires can be drawn. Electric wire is an example of ductility.

→ Malleability: It is a property of metals by virtue of which metals can be beaten into thin sheets.

→ Conductivity: Metals allow the passage of heat and electricity through them, this is called conductivity.

→ Mineral: Substances from which metals can be extracted are called minerals. Metals can be extracted from minerals by different methods.

→ Metallurgy: To extract metals from their ores and purify them for use is called metallurgy.

→ Ore: Those minerals from which metal extraction is easy and profitable are called ores.

→ Gangue: Ores mined from the earth are contaminated with impurities such as soil, sand, etc. are called gangue.

→ Roasting: The process of converting enriched ore in the excess of air is called roasting.

→ Reduction: It is a process of obtaining metals from compounds.

→ Purification: It is a process of obtaining pure metal from impure metal.

→ Alloy: Mixture of a metal with other metal or non-metal in the called alloy.

→ Allotropy: A property by virtue of which non-metals exist in different forms is called allotropy.

→ Vulcanization: Mixing sulphur with natural rubber is called vulcanization and such rubber is called vulcanized rubber.

→ Slag: It is a substance that is obtained when gangue and smelter are together.

→ Smelter: It is a substance which is used to separate gangue in the form of liquid from an impure metal.

→ Calcination: It is a process of heating ore in the limited supply of air. Ore becomes porous in this process.

→ Smelting: It is a process to extract an element from its ore using heat and a reduction agent.

→ Metals: Metals are those elements which lose electrons to form positive ions.

→ Non-Metals: Non-Metals are those elements which gain electrons to form negative ions.

→ Amalgam: When one of the constituents of an alloy is mercury it is called an alloy.

→ Corrosion: The effect of air, water, or any other substance on the surface of the metal is called corrosion.

→ Strategic metals: These are the metals that are important for the economy and safety of the country are strategic metals.

→ Electropositive elements: Those elements which lose electrons to form positive ions are known as electropositive elements: Metals belong to this category.

→ Electronegative elements: Those elements which gain electrons to form negative ions are known as electronegative elements. Non-metals belong to this category.

→ Reactivity series of metals: Arrangement of metals in a column in decreasing reactivity of metals is called reactivity series of metals.

→ Displacement reactions: The replacement of less reactive metal by more reactive metal from its salt in a reaction is called displacement reaction.

→ Catalyst: These are substances that do not take part in a reaction but can increase or decrease the rate of reaction are called catalysts.

→ Promotor: Substances that increase the performance of catalysts are called promotors.

This PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 2 Acids, Bases and Salts

→ The sour taste of foods is due to acids and the bitter taste is due to bases present in them. Acids turn blue litmus into red and bases turn the red litmus into the blue.

→ Acids and bases neutralize each other’s effects.

→ Acids and bases can be tested using litmus, turmeric, methyl orange, and phenolphthalein indicators.

→ On passing carbon dioxide gas through lime water, lime water turns milky.

→ On passing, excess carbon dioxide gas through lime water, its milky colour disappears due to the formation of soluble calcium bicarbonate.

→ Bases turn phenolphthalein pink in colour.

→ Acids and bases react to produce salt and water.

→ The flow of current in the solution is due to ions present in the solution.

→ In acids H+ ions are present. Acids produce hydrogen ion H⁺(aq) in a solution due to which solutions become acidic.

→ Bases produce hydroxide (OH^–) ions in water.

→ Alkali is a base that dissolves in water.

→ Bases are soapy to touch, bitter, and corrosive.

→ All acids produce H⁺(aq) and bases produce OH^–(aq) in an aqueous solution.

→ The process of the dissolving of acids or bases in water is highly exothermic, therefore to dilute them these should be added and mixed slowly in water. Never add water to concentrated acid.

→ A universal indicator is a mixture of several indicators.

→ Universal indicators show different colors for different concentrations of hydrogen ions in the solution.

→ A scale known as the pH scale has been developed for measuring the concentration of hydrogen ions present in the solution.

→ The ‘p’ in pH stands for ‘potenz’ this is a German word which means power.

→ On the pH scale, we can measure pH generally from 0 (very acidic) to 14 (very basic).

→ Higher is the concentration of hydronium ion, less is the value of pH. A neutral solution has a pH value of 7.

→ If the value of pH is less than 7 then the solution is acidic and if pH lies between 7 to 14 then the solution is basic.

→ Those acids which produce a large number of H⁺ ions are called strong acids and those acids which produce less H⁺ ions are weak acids.

→ Our body works in the range of 7.0 to 7.8.

→ When the pH value of rainwater is less than 5.6 it is called acid rain.

→ To get rid of acidity in the body, and antiacid like magnesium hydroxide which is a weak base is used.

→ If the pH value is less than 5.5 in the mouth, decay of teeth starts.

→ Nettle is a herbaceous plant that causes painful stings due to methanoic acid present in stinging hair. A traditional remedy is rubbing the area with the leaf of the dock plant.

→ Common salt (NaCl) is produced by the reaction between hydrochloric acid and sodium hydroxide.

→ Bleaching powder is produced by the action of chlorine on dry slaked lime.

→ Bleaching powder is used in the paper and textile industry for bleaching. It acts as an oxidant and as a disinfectant.

→ Baking soda (NaHCO₃) is produced from sodium chloride.

→ Sodium hydrogen carbonate is a mild non-corrosive base. It is used in the production of Baking powder and used in the preparation of cakes. It is also used in fire extinguishers.

→ Washing soda (NagCO₃.10H₂O) is prepared from sodium chloride. It is used in the glass, soap, paper industries. It is used to remove the permanent hardness of the water.

→ The chemical formula for hydrated copper sulfate is CuSO₄.5H₂O and of gypsum is CaSO₄.2H₂O.

→ Plaster of Paris is obtained from calcium sulphate hemihydrate (CaSO₄. \(\frac{1}{2}\) H₂O) by heating it at 373K.

→ Plaster of Paris is used for making toys and material for decoration.

→ Indicators: These are the substances that give different colors in acidic and basic solutions e.g. litmus, turmeric, phenolphthalein, methyl orange, etc.

→ Olfactory Indicators: There are some substances whose odour changes in acidic or basic media, which are known as olfactory indicators.

→ Acid: Those compounds which have one or more hydrogen atoms and which give hydrogen (H⁺) or hydronium (H₃O⁺) ions (H₃O⁺) ion in an aqueous solution are called acids. These are sour in taste.

→ Ionization: It is a process in which a substance produces ions in water, ionization.

→ Basicity of an acid: Basicity of an acid is the number of hydronium ions [H⁺] produced when one molecule of acid gets completely ionized in an aqueous solution.

→ Base: Bases are those compounds which are metal oxides or metal hydroxide or aqueous ammonia and these react with hydronium ion (H₃O⁺) of acids to produce salt and water.

→ Neutralization: Due to the reaction between acids and bases, salt and water are produced. This is called a neutralization reaction.

→ Alkali: Those basic hydroxides which on dissolving in water form hydroxyl (OH^–) ions, are called alkali.

→ Universal indicator: It is a mixture of various organic substances which show different colours with solutions having different pH values.

→ Dissociation: When a molecule or ionic compound dissociates into two or more atoms or ions, this is called dissociation.

→ Chemical dissociation: A reaction in which a molecule of a compound breaks into atoms or ions is called chemical dissociation.

→ The water of Crystallisation: Water, which is present in crystals of a substance is called water of crystallization. e.g., FeSO₄.7H₂O, Al₂O₃.2H₂O, CuSO₄.5H₂O, Na₂CO₃.10H₂O.

→ Efflorescence: The process of release of crystalline water from hydrated salts into the air is called efflorescence.

→ Deliquescence: This is a process in which a substance absorbs moisture from the atmosphere and dissolves in the absorbed water to form a solution.

→ Dilution: On mixing acid or base in water, the concentration of ions (H₃O⁺/OH^–) per unit volume becomes less. This is called dilution.

→ Chlor-alkali process: The electrolysis of sodium chloride solution is called chlor-alkali process.

This PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 1 Chemical Reactions and Equations

→ In a chemical reaction, old bonds in the reactants are broken forming new bonds to give products.

→ A chemical equation represents a chemical reaction.

→ By using chemical formulae instead of words, chemical equations can be made more useful and concise.

→ According to the law of conservation of mass matter (or Mass) can neither be created nor destroyed in a chemical reaction.

→ If the number of atoms of each element is the same on both sides of the arrow in a chemical reaction then the chemical equation is a balanced equation.

→ The method used to balance chemical equations is known as the Hit-and-Trial method since we make trials to balance the equation by using the smallest whole number coefficient.

→ The solid, gas, liquid, and aqueous states of reactants and products are represented by the notations: (s), (g), (l), and (aq) respectively.

→ When reactants and products are present as solutions in water then the word aqueous (aq) is written.

→ When (g) is written with water, it means that water is present in the form of vapour.

→ A reaction in which two or more reactants combine to form a single product is known as a combination reaction.

→ The chemical formula for marble is CaCO₃.

→ After two three days of whitewashing, calcium carbonate is formed which gives a shiny finish to the walls.

→ We get energy from food.

→ During digestion, food is broken into fine particles of simpler substances.

→ The decomposition of vegetable matter into compost is an example of an exothermic reaction.

→ A reaction in which a single reactant breaks down to give simpler products is called a decomposition reaction.

→ On heating, crystals of ferrous sulfate crystals lose water, and their color changes.

→ NO₂ fumes are brown in colour.

→ The white colour of silver chloride changes into a grey colour in sunlight.

→ The chemical reactions in which energy is given out are called exothermic reactions.

→ Those reactions in which energy is absorbed are known as endothermic reactions.

→ Those reactions in which there is an exchange of ions between the reactants are called double displacement reactions.

→ Those reactions in which precipitates are formed are known as precipitate reactions.

→ If in a reaction one of the reactants gets oxidized and the other gets reduced, then such a reaction is called a redox reaction.

→ In a reaction, a substance is oxidized when there is a gain of O₂ or a loss of H₂ in it.

→ A substance is reduced when it gains H₂ or loses O₂.

→ When a metal comes in contact with acid or moisture around it, gets corroded and the process is called corrosion.

→ Examples of corrosion are black coating on silver and green coating on copper.

→ Oxidation of oils and fats become rancid and their taste and smell change.

→ To slow down the oxidation process of food materials these are kept in air-tight containers.

→ Chemical change: It is a reaction in which new substances are formed. It is called a chemical change.

→ Chemical reaction: A process in which chemical change takes place is called a chemical reaction.

→ Reactants: Those substances which take part in a chemical reaction are called reactants.

→ Products: Those substances which are formed in a chemical reaction are called products.

→ Combination reaction: It is a chemical reaction in which two or more two substances combine to form a single substance.

→ Decomposition reaction: It is a chemical reaction in which a molecule breaks into molecules of simpler substances.

→ Displacement reaction: A reaction in which a substance displaces another substance is called a displacement reaction.

→ Double displacement reaction: This is a reaction in which there is a mutual exchange between two different atoms or groups of atoms.

→ Neutral solution: When an acid and a base are mixed in a proper proportion, then we get a neutral solution.

→ Neutralisation reaction: When we get salt and water as the only products by mixing acid and base, then such a reaction is known as a Neutral reaction.

→ Oxidation: A substance is oxidized when there is a gain of oxygen or a loss of hydrogen in the substance.

→ Reduction: A substance is reduced when there is a loss of oxygen and a gain of hydrogen in the substance.

→ Redox reaction: A reaction in which oxidation and reduction both take place simultaneously is called a redox reaction.

→ Exothermic reaction: Those reactions in which heat is produced along with the products are called exothermic reactions.

→ Endothermic reactions: Those reactions in which heat is absorbed are called endothermic reactions.

→ Precipitation reactions: When two solutions are mixed and due to reaction between them a white coloured substance (or some other colour) is formed which is insoluble in water, then this is called a precipitation reaction.

→ Fermentation: The change of carbonic substances with the help of microorganisms or enzymes into simple carbonic substances is called fermentation.

→ Rancidity: When fat/oil-containing food materials are left for a long time then due to oxidation there is a change in their smell and taste, this change is called rancidity.

→ Reducing agent: That substance that gets oxidised itself or reduces the other substances by giving electrons is called a reducing agent.

→ Oxidizing agent: That substance that gets reduced itself or oxidizes the other substances by gaining electrons is called an oxidizing agent.

This PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 12 Western Sociological Thinkers

→ During the 19th and 20th centuries, many changes came in the European society and it is said that Sociology originated to study such changes.

→ From the 17th-19th centuries, many philosophers wrote new books which gave a great contribution to the emergence of sociology. Montesquieu and Rousseau are quite important among them.

→ Auguste Comte was a French philosopher and is considered as the Father of Sociology.

→ He wrote a book ‘The Course on Positive Philosophy’ in which in 1839, he used the word ‘Sociology’. He called it a science of society.

→ Comte gave the theory of Positivism and said that social phenomenon can also be understood with scientific explanation and positivism is that method.

→ So, positivism is the systematic method of observation, experience, comparison, and historical method with which society can be scientifically studied.

→ Comte studied different societies and said that to reach the present stage, society had to cross through three stages and these stages are the Theological stage, Metaphysical stage, and Positivistic stage. This is Comte’s law of three stages.

→ Karl Marx was a German Philosopher who is known for his views given on class and class struggle.

→ The concepts of communism and socialism were also given by Karl Marx.

→ Marx was of the view that the history of society, is the history of class struggle.

→ There exist two classes in all the societies-capitalist class which owns all the means of production and labour class which is not having anything to sell except its labour.

→ There is the existence of conflict between the both to get more and this is known as class struggle.

→ Emile Durkheim is also known as one of the founding fathers of sociology.

→ He tried to establish sociology as a science. He was the first professor in the subject of sociology.

→ Durkheim gave a great contribution to the subject of sociology and some of the important concepts given by him are the concept of Social Fact, Theory of Suicide, the theory of Division of Labour, the Concept of Religion, etc.

→ Durkheim was of the view that the concept of division of labour existed in society right from ancient times.

→ The nature of society is determined due to the division of labour.

→ Max Weber is one of the important sociologists and founding fathers of sociology.

→ Like Marx, he was also a German Philosopher.

→ He gave many concepts to sociology such as the concept of social action, Verstehen, Protestant Ethics and Spirit of Capitalism, Authority and its types, Bureaucracy, etc.

→ Class: Group of people whose means of production are common.

→ Authority: It is a form of power supported by the norms of a social system and accepted as legitimate by those who participate in it.

→ Social Action: It is an act that cares about the actions and reactions of individuals. If the acting individual takes account of others’ behaviour, it is social.

→ Class Consciousness: The awareness among members of a class about their common motives.

→ Class Struggle: There exists a conflict of interests between capitalist and labour classes. This conflict of interests becomes a reason for class struggle. When class consciousness increases among the people, class struggle also increases.

→ Positivism: In positivism, it is considered that society acts according to certain rules which can be discovered.

→ Mechanical Solidarity: The sense of unity among the members of a homogeneous society is called mechanical solidarity.

→ Organic Solidarity: In many societies, people have differences among them and that’s why they depend upon each other. The unity which exists in such a society is known as organic solidarity.

This PSEB 11th Class Sociology Notes Chapter 11 Social Change will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 11 Social Change

→ Change is the law of nature. There is nothing in this world that has not yet changed. Even nature changes itself from time to time.

→ When change comes in different parts of society and the change affects the structural change comes in the ways of living of the people.

→ There are many features of social change such as it is a universal process, speed of changes is different in different societies, it is community change, no prediction regarding change is possible, it is the result of many interactions, it can be planned as well as unplanned, etc.

→ There are many types of social change such as evolution, development, progress, and revolution.

→ Many a time these words are used for each other but in Sociology, they are very much different from each other.

→ The meaning of evolution is equal change internally. This is a very slow process and social institutions change from simple to complex.

→ Development is also an aspect of social change.

→ When change comes in anything in the desired direction, it is known sis development.

→ Different sociologists have given different bases of development.

→ Progress is another type of social change. It means to move towards achieving objectives.

→ Progress is the efforts made to achieve objectives which is definite and which get scope ration from social values.

→ Revolution brings a sudden and fast change in society with which old structure comes to an end and new structure comes forward.

→ Many a time people become so dissatisfied that they stand up against the system. It is known as revolution.

→ The revolution of 1789 A.D. in France was a change of such type.

→ Many factors influence the direction and speed of social change such as natural factors, beliefs, and values, social reforms, demographic factors, technological factors, educational factors, etc.

→ Diffusion: The process by which cultural traits spread from one culture to another.

→ Innovation: Introduction of new ideas, techniques, etc., and better use of existing ideas and technology.

→ Social Change: Change in the functions of social structure and social system.

This PSEB 11th Class Sociology Notes Chapter 10 Social Stratification will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 10 Social Stratification

→ Inequality exists everywhere in society, Someone is black, white, poor, rich, thin, fat, literate, or illiterate. There are many other bases which we can find in our society.

→ Divison of society in different layers on different bases is known as social stratification.

→ We cannot find any society where stratification doesn’t exist.

→ It exists everywhere in ancient societies, medieval societies, and modern societies.

→ Stratification has many features such as is a universal process, is social in nature, its type is different in different societies, relations in it are based on superiority and inferiority.

→ Mainly four forms of stratification are available in our societies and these are caste, class, feudalism, and slavery.

→ Indian society is greatly influenced by the caste system.

→ A caste is an endogamous group that keeps certain restrictions on its members regarding relationships, social intercourse, etc. The caste of an individual was fixed according to his birth.

→ In modern societies, a new form of stratification has come forward and this is the class system.

→ Class is a group of people who are similar to each other on a particular basis.

→ For example, upper class, middle class, lower class, labour class, industrialist class, doctor class, etc.

→ Feudalism was one of the important aspects of medieval European society.

→ One individual was given a very large piece of land and was made feudal lord.

→ This land was transmitted to his children with which they remained rich.

→ During the 19th and 20th centuries, slavery prevailed in many parts of the world.

→ One person was purchased and sold as a slave and the owner kept unlimited rights over him.

→ G.S. Ghurye was one of the Indian sociologists who gave his views on the caste system.

→ According to him, the caste system is so complex that it is not possible to define it.

→ That’s why he gave six features of the caste system.

→ After the Indian independence, many changes came in the caste system and the changes are still going on.

→ Now caste system is declining day by day.

→ Caste restrictions no more prevail, caste privileges come to an end, constitutional provisions provide equality to all and all these factors have played a very important role in the decline of this system.

→ Many factors contributed to bringing changes in the caste system such as socio-reform movements, modern education, urbanisation, modernisation, industrialisation, development of means of transport and communication, constitutional provisions, etc.

→ Mainly three types of classes prevail in our society: Upper class, middle class, and lower class. The difference between these classes is mainly on the basis of wealth.

→ A caste is a closed group which cannot be changed in any case but a class is an open group that can be changed with an individual’s ability and hard work.

→ According to Karl Marx, in different ages, there prevailed two classes.

→ The first one is the capitalist class and the second one is labour class.

→ The conflict remained there, between them, all the time and this is known as class conflict.

→ New trends are also coming into the class system. During the last few decades, a new class has emerged and this is the middle class.

→ The upper class always exploited the lower class with the help of the middle class.

→ Varna: During ancient times, society was divided into many parts on the basis of Occupation, and each part was known as varna. There were four Varnas-Brahmin, Ksljatriya, Vaishya, and Shudra.

→ Caste: An endogamous group that keeps certain restrictions on its members regarding social intercourse.

→ Class: The economic group which can be differentiated from the other economic group on any basis.

→ Feudalism: During the medieval period, there prevailed a very powerful system in the medieval European society in which one person was made a feudal lord by giving a large piece of land. He was authorized to collect tax from the farmer.

→ Stratification: The process of dividing society into different layers on different bases is known as stratification.

This PSEB 11th Class Sociology Notes Chapter 9 Social Structure will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 9 Social Structure

→ There are many basic concepts of sociology and social structure is one of them.

→ Herbert Spencer was the first Sociologist who used the word social structure.

→ After him, many other Sociologists such as Talcott Parsons, Radcliffe Brown, Maclver, etc. also wrote about it.

→ Society has many parts which are connected in. one way or the other. All these parts are interrelated.

→ The systematic form of these interconnected parts is known as social structure.

→ All these parts are abstract but they direct us in one way or the other.

→ Social structure has many features. For example, it is abstract, it has many inter-related parts, one system exists in all of its parts, it regulates our behaviour, it is universal, it expressed the exterior form of society, etc.

→ Herbert Spencer wrote a book ‘The Principles of Sociology’ in which he used the word social structure and compared it with the living body.

→ He was of the view that the way in which different parts of the human body are needed for its smooth functioning, in the same way, different parts of social structure play a very important role in its smooth functioning.

→ There are several elements of social structure and status and role are quite important among all.

→ The meaning of status is the position given to an individual while living in society.

→ One person is given many a status such as officer, father, son, President of a club, etc.

→ Status is of two types – Ascribed and Achieved.

→ Ascribed status is that which one gets automatically without any effort.

→ Achieved status is that which one gets due to his efforts and ability.

→ The role is the collection of expectations that are expected to be fulfilled by an individual.

→ Many roles are attached to each status. Only with the role, we come to know that how anyone will act while sitting on a particular status.

→ There are many features of the role such as it is learned, it is the functional aspect of status, it has a psychological base, etc.

→ Status and role are deeply related as they are the two sides of the same coin.

→ If anyone is given a status then automatically role is attached with the status.

→ Without a role, status is of no importance and without status, the role cannot be performed.

→ Social Structure: Orderly arrangement of different parts is known as social structure.

→ Role Set: When someone gets many roles.

→ Role Conflict: When an individual gets many roles and a conflict starts among them.

→ Role: The expected behaviour of an individual who holds a particular status.

→ Status: Status is the social position of an individual which he needs to obey.

→ Ascribed Status: The status which one gets on the basis of birth.

→ Achieved Status: The status which is achieved through skill and talent.

This PSEB 11th Class Sociology Notes Chapter 8 Polity, Religion, Economy and Education will help you in revision during exams.

PSEB 11th Class Sociology Notes Chapter 8 Polity, Religion, Economy and Education

→ There exist many institutions in our society. In social institutions, we can include marriage, family, and kinship.

→ Except for social institutions, there are many other institutions such as political, religious, economic, educational, etc.

→ Political System is a sub-system of society. It fixes such human roles which are necessary to maintain law and order in society. There is a great relationship between polity and society.

→ In Sociology, information on political institutions is used to understand many concepts such as power, leadership, authority, etc. Such political institutions help us in maintaining peace and security in society.

→ Power is the ability of individuals or groups to carry out their will even when opposed by others.

→ A definite and fixed amount of power exists in society.

→ Few groups have more power and they exercise their power over the group which is having less power.

→ Power is applied with the help of an authority. Authority is a form of power that is considered just and legitimate.

→ Those who have authority, use power because they consider it justified.

→ Different societies have different states. In a few societies, there is no concept of state and they are considered stateless societies.

→ Such states existed in ancient societies. In modern societies, authority is included in the concept of state and it is obtained from the people.

→ Max Weber gave three types of authority-traditional, legal and charismatic.

→ Father’s authority is traditional, Government’s authority is legal, and accepting any leader’s will is called charismatic authority.

→ The state is the basic institution of the political system. It has four essential elements and these are population, geographical area, sovereignty, and government.

→ There are three organs of government and these are-Legislature, Executive, and Judiciary.

→ To maintain State and government, a proper balance between these three organs is necessary.

→ The present-day political system runs with democracy. It is of two types—direct and indirect.

→ In a direct democracy, people decide on their own and in indirect democracy, people’s elected representatives make all the decisions.

→ The government in our country has adopted the decentralized system and govts, are made till local level.

→ In rural areas, Panchayat is established at the village level, Block Samiti at the block level, and Zila Parished at the district level and they are responsible for doing development in their respective areas.

→ In a democracy, political parties keep a very important place.

→ A political party is a group of people whose main objective is to attain power by contesting elections.

→ Few parties are national parties and few are regional parties.

→ Interest groups keep a very important place in a democracy.

→ They are attached to any particular group and they work to achieve the interests of their group.

→ Religion has existed in society since the time when human society started.

→ Religion is nothing but faith in super-natural power that is beyond our existence and reach.

→ Many religions exist in our country India such as Hinduism, Islam, Christianity, Sikhism, Buddhism, Jainism, Zoroastrianism (Parsi), etc.

→ India is a multi-religious country where people of many religions live in peace and harmony with each other.

→ Every person needs money to buy food, cloth, house, health services, etc. and all these are important parts of our economy. Economic institutions take care of our income and expenditure.

→ Different societies have different economies. Few societies have collective economies, few are pastoral economies, rural economies, industrial economies, and capitalist economies. Karl Marx also gave a new economy called socialist economy.

→ The concept of division of labor is not new to our society.

→ When people start to do specific work and are unable to do all the works, it is called specialisation and division of labour.

→ The caste system and Jajmani system in India are one such type of division of labour.

→ If we observe our society, we can say that nothing in our society, is possible without education.

→ Education changes an uncivilized person into a civilized individual.

→ Education is of two types – formal and informal.

→ Formal education is that which we get in school, college, etc. and informal education is that which we get from our daily life experiences.

→ Authority: Power established by the political system in its geographical area.

→ Division of Labour: The system in which occupations are divided into different parts and every occupation is given to an individual or group.

→ Economy: System of production, distribution, and consumption.

→ Globalisation: The process of international integration arising from the interchange of world views, ideas, products, and other aspects of culture.

→ Totem: Considering any tree, plant, stone, or any other thing as sacred.

→ State Society: The society in which formal organisation of government exists.

→ Stateless society: The society in which there is no formal organisation of government.

→ Pressure groups: Such groups in a democratic system work for the interests of a particular group.

→ State: State is a group with four essential features – population, geographical area, sovereignty, and government.