Chemistry : ✓ The branch of science that studies the preparation, properties, structure and reactions of material substances is called chemistry Branches of Chemistry: 1. Organic chemistry - Study of carbon and its compounds. 2. Inorganic chemistry - Study of Elements oth er than carbon and their compounds. 3. Physical chemistry - Study of laws & theories of chemical reactions. 4. Analytical chemistry - Study of Qualitative and Quantitative analysis. Qualitative analysis : Identification of chemical substance. Quantitative analysis : Determination of amount of chemical substance. → Biochemistry - S tudy of reactions occuring in living things. → pharmaceutical chemistry - S ynthesis & devolopement of medicines. → Agricultural chemistry - Synthesis of chemicals which are helpful in agricultural production. ✓ Symbols : Abbreviations used to represent the elements. Atomic Number Element Symbol Atomic Number Element Symbol 1 Hydrogen H 16 Sulphur S 2 Helium He 17 C hlorine Cl 3 Lithium Li 18 Argon Ar 4 Beryllium Be 19 P otassium K 5 Boron B 20 C alcium Ca 6 Carbon C 21 Scandium Sc 7 Nitrogen N 22 Titanium Ti 8 Oxygen O 23 Vanadium V 9 Fluorine F 24 Chromium Cr 10 Neon Ne 25 M anganese Mn 11 Sodium Na 26 Iron Fe 12 M agnesium Mg 27 Cobalt Co 13 Aluminium Al 28 Nickel Ni 14 S ilicon Si 29 Copper Cu 15 P hosphorus P 30 Zinc Zn ✓ Symbols of the elements der i ved from latin names Element Symbol Latin name Sodium Na Natrium Potassium K Kalium Copper Cu Cuprum Iron Fe Ferrum Gold Au Aurum Lead Pb Plumbum Mercury Hg Hydragyrum Silver Ag Argentum Tin Sn Stannum Tungsten W Wolfram Antimony Sb Stibium Formula : ✓ Symbolic representation of a molecule Ex : Water → H 2 O Sulphuric acid → H 2 SO 4 Radical : ✓ Group of atoms possessing charge. ✓ Basic radical : radical having positive charge Ex: Na + , 4 NH + etc ✓ Acid radical : radical having negative charge. Ex : Cl − , Br − etc Cations Anions Sodium, Na + Fluoride, F − Potassium, K + Chloride, Cl - Silver, Ag + Bromide, Br − Cuprous, Cu + Iodide, I − Cupric, Cu 2+ Hydroxide, OH − Mercurous , Hg + Nitrite, 2 NO − Mercuric, Hg 2+ Nitrate, 3 NO − Ferrous, Fe 2+ Carbonate, 2 3 CO − Ferric, Fe 3+ Bicarbonate, 3 HCO − Stannous, Sn 2+ Sulphite, 2 3 SO − S tannic, Sn 4+ Sulphate, 2 4 SO − Ammonium, 4 NH + Chromate, 2 4 CrO − Barium, Ba 2+ Dichromate, 2 2 7 Cr O − Calcium, Ca 2+ Phosphite, 3 3 PO − Magnesium, Mg 2+ Phosphate, 3 4 PO − Aluminium, Al 3+ Sulphide, S 2 - Strontium, Sr 2+ Oxide, O 2 - Zinc, Zn 2+ Peroxide, 2 2 O − Lead, Pb 2+ Nitride, N 3 - Manganate, 2 4 MnO − Permanganate, 4 MnO − Examples: 1. Write the formula of sodium sulphide Ans: Na 2 S 2. Write the formula of aluminium sulphate Ans: Al 2 (SO 4 ) 3 3. Write the formula of calcium carbonate Ans: CaCO 3 4. Write the formula of calcium nitrate Ans: Ca(NO 3 ) 2 Exercise: 1.1 Sl. No Name Formula 1 Cupric chloride 2 Cuprous chloride 3 Barium nitrate 4 Ferrous sulphate 5 Ferric sulphate 6 Ammonium sulphate 7 Calcium bicarbonate 8 Aluminium hydroxide 9 Sodium carbonate 10 Sodium phosphate 11 Magnesium chloride 12 Magnesium sulphate 13 Zinc sulphide 14 Zinc sulphate 15 Potassium nitrate 16 Potassium sulphate 17 Potassium permanganate 18 Potassium dichromate 19 Magnesium carbonate 20 Ammonium phosphate 21 Ammonium chloride 22 Barium sulphate 23 Barium chloride 24 Calcium nitrate Exercise: 1. 2 Sl. No Formula Name of the compound 1 Cu 2 O 2 Na 2 SO 3 3 K 2 SO 4 4 BaCl 2 5 NH 4 NO 3 6 Ca(OH) 2 7 Pb(NO 3 ) 2 8 AlCl 3 Chemical reaction : ✓ Pr ocess that leads to transformation of one kind of matter into another kind of matter. C(s) + O 2 (g) ⎯⎯ → CO 2 (g) CaCO 3 (s) ⎯⎯ → CaO(s) + CO 2 ( g ) CH 4 (g) + 2 O 2 (g) ⎯⎯ → CO 2 (g) + 2 H 2 O(l) ✓ Reactants : Substances which are initially present in a chemical reaction ✓ Products : substances that are formed after completion of the reaction. Reactants Products A + B C + D ⎯⎯ → Chemical equation : ✓ Representation of a chemical change in terms of symbols and formula of reactants and products. Heat (as a ribbon) (From air) (White powder) Heat 2 Ex : Magnesium + Oxygen Magnesium Oxide 2Mg(s) + O (g) 2MgO(s) ⎯⎯⎯ → ⎯⎯⎯ → 2 2 Zinc + Hydrochloric acid Zinc Chloride + Hydrogen Zn(s) + 2HCl(aq) ZnCl (aq) + H (g) ⎯⎯ → ⎯⎯ → ✓ Products and reactants are separated by arrow ( → ). ✓ Individual substances are separated by (+) sign. Balanced chemical equation : ✓ Contains equal number of atoms of each element on both sides of the equation. 2 2 2 H + O H O [Unbalanced] ⎯⎯ → → Skeletal equation ✓ 2 2 2 2H + O 2H O [Balanced] ⎯⎯ → ✓ 2 2Mg + O 2MgO [Balanced] ⎯⎯ → Example s : ✓ Balance the following equations. 1. ⎯⎯ → 2 3 4 2 Fe + H O Fe O + H Ans: 2 3 4 2 3Fe(s) + 4H O(g) Fe O (s) + 4H (g) ⎯⎯ → 2. ⎯⎯ → 2 2 2 2 MnO + HCl MnCl + Cl + H O Ans: 2 2 2 2 MnO + 4HCl MnCl + Cl + 2H O ⎯⎯ → 3. ⎯⎯ → 2 3 Al + Cl AlCl Ans: 2 3 2Al + 3Cl 2AlCl ⎯⎯ → 4. ⎯⎯ → 2 2 H S + Cl HCl + S Ans: 2 2 H S + Cl 2HCl + S ⎯⎯ → Exercise : 1.3 Sl. No Unbalanced equation Balanced equation 1 2 2 3 SO + O SO ⎯⎯ → 2 2 2 NO + O NO ⎯⎯ → 3 3 2 KClO KCl + O ⎯⎯ → 4 3 2 2 2 Zn(NO ) ZnO + NO + O ⎯⎯ → 5 2 3 Li + N Li N ⎯⎯ → 6 2 3 2 Mg + N Mg N ⎯⎯ → 7 2 2 3 N + H NH ⎯⎯ → Sl. No Unbalanced equation Balanced equation 8 3 4 2 Pb O PbO + O ⎯⎯ → 9 2 2 3 Al + O Al O ⎯⎯ → 10 2 2 2 HCl + O Cl + H O ⎯⎯ → 11 2 3 Fe + Cl FeCl ⎯⎯ → Types of Chemical reactions: 1. Combination reactions ✓ The reactions in which two or more substances combine to form a single substance. Examples of combination reactions Combination of two elements to form a compound: ✓ Combustion of coal: Coal burns in air to form carbon dioxide gas 2 2 C(s) + O (g) CO (g) ⎯⎯ → ✓ Combustion of hydrogen: hydrogen burns in oxygen to form water which is initially in the gaseous state i.e., steam. Upon cooling, it becomes liquid. 2 2 2 2H (g) + O (g) 2H O(l) ⎯⎯ → Combination of an element and a compound to form a new compound: ✓ Combination between nitric oxide and oxygen: 2 2 2NO(g) + O (g) 2NO (g) ⎯⎯ → ✓ Formation of Sulphur trioxide: 2 2 3 2SO (g) + O (g) 2SO (g) ⎯⎯ → Combination of two compounds to form a new compound: ✓ Combination between ammonia and hydrogen chloride gas 3 4 NH (g) + HCl(g) NH Cl(g) ⎯⎯ → ✓ Formation of Calcium sulphate: 3 4 CaO(s) + SO (g) CaSO (s) ⎯⎯ → ✓ Reaction between calcium oxide and water: 2 2 CaO(s) + H O(l) Ca(OH) (aq) + Heat ⎯⎯ → 2. Decomposition reactions: ✓ The reactions in which a single substance splits into two or more simpler substances are known as decomposition reactions. ✓ There are three types of decomposition reaction A) Thermal decomposition reaction: ✓ When a decomposition reaction is carried out by heating, it is called thermal decomposition reaction. Heat 4 2 3 2 3 2FeSO (s) Fe O (s) + SO (g) + SO (g) Ferrous sulphate Ferric oxide ⎯⎯⎯ → Heat 3 2 2 2 2Pb(NO ) (s) 2PbO(s) + 4NO (g) + O (g) ⎯⎯⎯ → Heat 3 2 CaCO (s) CaO(s) + CO (g) Limestone Quick lime ⎯⎯⎯ → B) Electrolytic decomposition reaction: ✓ When a substance is decomposed by passing electric current, the process is called electrolysis (electro= electric, lysis=breakdown). ✓ Example: when an electric current is passed through water (mixed with few drops of aci d), it is decomposed into hydrogen and oxygen gases. Electric current 2 2 2 2H O(l) 2H (g) + O (g) ⎯⎯⎯⎯⎯ → C) Photodecomposition reactions: ✓ When a chemical compound decomposes on absorbing light energy, so as to form two or more substances, then the reaction which takes place is ca lled photodecomposition reaction. Sunlight 2 2AgCl(s) 2Ag(s) + Cl (g) ⎯⎯⎯→ Sunlight 2 2AgBr(s) 2Ag(s) + Br (g) ⎯⎯⎯→ 3. Displacement reactions: ✓ The chemical reactions in which one element takes the position or place of another element present in a compound ✓ In these reactions, an atom or group of atoms in a molecule is replaced by another atom or a group of atoms. 4 4 Fe(s) + CuSO (aq) FeSO (aq) + Cu(s) Copper sulphate Iron sulphate ⎯⎯ → In this reaction, Iron has displaced or removed another element, Copper f rom copper sulphate solution. 4 4 Zn(s) + CuSO (aq) ZnSO (aq) + Cu(s) Copper sulphate Zinc sulphate ⎯⎯ → 2 2 Pb(s) + CuCl (aq) PbCl (aq) + Cu(s) Copper chloride Lead chloride ⎯⎯ → ✓ Lead and Zinc are more reactive elements than copper. They displace copper from its compounds. 4. Double displacement reactions: ✓ Reactions in which there is an exchange of ions between the reactants are called double displacement reactions. 2 4 2 4 Na SO (aq) + BaCl (aq) BaSO (s) + 2NaCl(aq) Sodium sulphate Barium chloride Barium sulphate Sodium chloride ⎯⎯ → ✓ In this reaction a white substance, which is insoluble in water, is formed. This insoluble substance formed is known as a precipitate. ✓ Any reaction that produces a precipitate can be called a precipitation reaction. 5. Oxidation and reduction reactions: Oxidation: The process of addition of oxygen / any electronegative element to a substance OR removal of hydrogen / any electropositive element from a substance is called oxidation. Reduction: The process of addition of hydrogen / any electropositive elem ent to a substance OR removal of oxygen / any electronegative element from a substance is called reduction. Examples: Δ ZnO + C Zn + CO ⎯⎯ → Gain of Oxygen Loss of Oxygen Oxidation Reduction PbO + C Pb + CO ⎯⎯ → Gain of Oxygen Loss of Oxygen Oxidation Reduction 2 2 CuO + H Cu + H O ⎯⎯ → Gain of Oxygen Loss of Oxygen Oxidation Reduction 2 2 H S + Cl 2HCl + S ⎯⎯ → Gain of Hydrogen Loss of Hydrogen Oxidation Reduction 2 2 2 2 MnO + 4HCl MnCl + 2H O + Cl ⎯⎯ → loss of Hydrogen Loss of Oxygen Oxidation Reduction 2 2 Mg + F MgF ⎯⎯ → addition of addition of Oxidation Reduction electronegative element electropositive element ✓ Oxidation and Reduction always occur simultaneously hence the word redox was coined for this class of reactions. Redox reactions in terms of e lectron transfer reactions: Oxidation: Loss of electron(s) by any species is called oxidation. Reduction: Gain of electron(s) by any species is called reduction. Example: + 2 2Na(s) + Cl (g) 2Na Cl (s) − ⎯⎯ → gain of 2 electrons loss of 2 electrons Oxidation Reduction ✓ This reaction can be written in two steps + 2Na(s) 2Na + 2e (oxidation half reaction) − ⎯⎯ → 2 Cl (g) + 2e 2Cl (reduction half reaction) − − ⎯⎯ → ✓ Sum of these half reactions gives overall reaction Overall reaction: + 2 2Na(s) + Cl (g) 2Na Cl (s) − ⎯⎯ → ✓ NOTE: Shortcut to remember oxidation and reduction in terms of electron transfer OIL – oxidation is loss o f electron(s). RIG – reduction is gain of electron(s). Reducing agent/reductant: ✓ Species which loose one or more electron(s) ✓ Reducing agent itself undergoes oxidation during the redox reaction. Oxidizing agent/oxidant: ✓ Species which gains one or more ele ctron(s) ✓ Oxidizing agent itself undergo reduction during redox reaction. Example: + 2 2Na(s) + Cl (g) 2Na Cl (s) − ⎯⎯ → gain of 2 electrons loss of 2 electrons Oxidation Reduction Reducing agent – Na Oxidizing agent – Cl 2 Oxidation number: ✓ Oxidation number of an element is defined as the actual or apparent charge carried by an atom of the element in the substance. Rules for calculating oxidation number: 1. Oxidation number of any element in its elementary state is zero. Example: oxidation number of each atom in N 2 , H 2 , O 2 , Cl 2 , O 3 , P 4 , S 8 , Na, Mg, Al is zero. 2. Oxidati on number of element in monoatomic ion is equal to charge carried by the monoatomic ion. Example: oxidation number of Na in Na + is +1, Mg in Mg 2+ is +2, Fe in Fe 3+ is +3, Cl in Cl - is - 1, O in O 2 - is - 2. 3. Oxidation number of alkali metals is +1, oxidation number of alkaline earth metals is +2, and oxidation number of aluminium is +3. 4. The common oxidation number of Oxygen in its compounds is - 2. Exceptions: In peroxides (Ex: H 2 O 2 , Na 2 O 2 ) it is - 1 In superoxide (Ex: KO 2 , RbO 2 ) it is - 1/2 In OF 2 it is +2 In O 2 F 2 it is +1 5. Oxidation number of Hydrogen is always +1 in combined state except in metal hydrides (Ex: NaH, LiH, KH, CaH 2 , etc.) where it is - 1. 6. Fluorine is the most electronegative element. Hence the oxidation number of Fluorine in all its compounds is - 1. 7. Cl, Br, I have oxidation number - 1, when they occur as halide ion in their compounds. Cl, Br, I , when they combined with Oxygen shows positive oxidation number. Example: +1 +1 2 H Cl O − 8. Sum of the oxidation numbers of all the atoms in a neutral compound is equal to zero. 9. The sum of oxidation numbers of all the atoms in a polyatomic ion is equal to the charge on the ion. Example: sum of oxidation number of three oxygen atom and one carb on atom in the carbonate ion ( 2 3 CO − ) is equal to - 2. ✓ Oxidation number is also called oxidation state. Examples: 1. Calculate the oxidation number of ‘C’ in CO 2 Solution: Let oxidation number of ‘C’ = x. Oxidation number of each ‘O’ atom = − 2 Sum of oxidation numbers of all atoms = x + 2( − 2) = x − 4 It is a neutral molecule. Its sum must be equal to zero. x – 4 = 0 x = +4 2. Calculate the oxidation number of ‘Mn’ in KMnO 4 S olution: Let oxidation number of ‘Mn’ = x. Oxidation number of each ‘O’ atom = − 2 Oxidation number of each ‘K’ atom = + 1 Sum of oxidation numbers of all atoms = 1(+1) + x + 4( − 2) = x − 7 It is a neutral molecule. Its sum must be equal to zero. x – 7 = 0 x = +7 3. Calculate the oxidation number of ‘Cr’ in 2- 2 7 Cr O Solution: Let oxidation number of ‘Cr’ = x. Oxidation number of each ‘O’ atom = - 2 Sum of oxidation numbers of all atoms = 2x + 7( - 2) = 2x - 14 Sum must be equal to - 2. 2x – 14 = - 2 x = +6 Exercise : 1.4 1. Calculate the oxidation number of ‘Cr’ in 3 CrO 2. Calculate the oxidation number of ‘ N ’ in HNO 3 3. Calculate the oxidation number of ‘ Al ’ in AlCl 3 4. Calculate the oxidation number of ‘ S ’ i n H 2 SO 4 5. Calculate the oxidation number of ‘ Mn ’ i n MnO 2 6. Calculate the oxidation number of ‘Cr’ i n H 2 CrO 4 7. Calculate the oxidation number of ‘ N ’ i n NH 3 8. Calculate the oxidation number of ‘ C ’ i n CH 4 9. Calculate the oxidation number of ‘ P ’ i n PCl 5 10. Calculate the oxidation number of ‘ C ’ in 2 3 CO − 11. Calculate the oxidation number of ‘ P ’ in 3 4 PO − 12. Calculate the oxidation number of ‘ N ’ in 2 NO − 13. Calculate the oxidation number of ‘ N ’ in 3 NO − Redox reactions in terms of oxidation number Oxidation: ✓ Increase in the oxidation number of the element in the given substance is called oxidation. Reduction: ✓ Decrease in the oxidation number of the element in the given substance is called reduction. Example: 0 0 4 2 2 2 C + O CO + − ⎯⎯ → Reducing agent - C Oxidising agent - O 2 Oxidation Reduction Increase in oxidation number Decrease in oxidation number Electronic configurations of the elements : ✓ Order of energies of orbitals : 1s , 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 4f, 5d, 6p, 7s. ✓ ‘one - s’ – orbitals can accommodate 2 electrons. ✓ ‘three - p’ – orbitals can accommodate 6 electrons. ✓ ‘five - d’ – orbitals can accommodate 10 electrons. ✓ ‘seven - f’ – orbitals can accommodate 14 electrons. Exercise : 1.5 Complete the following table Atomic Number Element Electronic configuration Atomic Number Element Electronic configuration 1 H 1s 1 16 S 2 He 1s 2 17 Cl 3 Li 1s 2 2s 1 18 K 4 Be 1s 2 2s 2 19 Ar 5 B 1s 2 2s 2 2p 1 20 Ca 6 C 1s 2 2s 2 2p 2 21 Sc 7 N 1s 2 2s 2 2p 3 22 Ti 8 O 1s 2 2s 2 2p 4 23 V 9 F 1s 2 2s 2 2p 5 24 Cr 10 Ne 1s 2 2s 2 2p 6 25 Mn 11 Na 1s 2 2s 2 2p 6 3s 1 26 Fe 12 Mg 1s 2 2s 2 2p 6 3s 2 27 Co 13 Al 1s 2 2s 2 2p 6 3s 2 3p 1 28 Ni 14 Si 1s 2 2s 2 2p 6 3s 2 3p 2 29 Cu 15 P 1s 2 2s 2 2p 6 3s 2 3p 3 30 Zn Valency: ✓ Combining capacity of an element. ✓ H - H , Valency of ‘H’ = 1 ✓ C H H H H Valency of ‘C’ = 4 ✓ N H H H Valency of ‘N’ = 3 ✓ H O H Valency of ‘O’ = 2 ✓ F - F , Valency of ‘F’ = 1 ✓ H - Cl , Valency of ‘Cl’ = 1 ✓ H - Br , Valency of ‘Br’ = 1 ✓ H - I , Valency of ‘I’ = 1 Examples: Write the structure of Following compounds. 1. CH 3 Cl 2. (CH 3 ) 2 CO 3. CH 3 CN 4. HCONH 2 Ans: 1. 2. 3. 4. C H H H Cl C C C O H H H H H H C H H H C N H C N O H H Exercise: 1.6 Write the structure of Following compounds. 1. CH 3 CH=CHCN 2. HCHO 3. CH 2 =C=CHCH 3 4. CH 3 CH(OH)CH 3 5. CH 3 COOH 6. (CH 3 ) 3 COH 7. CH 3 CH 2 CH=CHCH 2 OH 8. NH 2 CONH 2 9. 3 CH C CH Atomic number (Z): ✓ The number of protons present in the nucleus of an atom is known as atomic number. ✓ It is also equal to the number of electrons present in a neutral atom. Mass number (A): ✓ It is the sum of the number of protons and the neutrons present in the nucleus of the atom. ✓ The protons and neutrons toget her called nucleons. ✓ Thus, Z = atomic number = number of protons = number of electrons in a nuetral atom. ✓ A = mass number = number of protons + number of neutrons ✓ Therefore A – Z = number of neutrons. Symbolic representation: X Z A Mass number Atomic number Symbol of the element Isotopes : ✓ Atoms having same atomic number but different mass numbers are called as isotopes. ✓ They contain same number of protons but differ in number of neutrons. Examples : i . Isotopes of hydrogen : Protium 1 1 ( H) , deuterium 2 1 ( H) , tritium 3 1 ( H) ii. Isotopes of carbon : 12 6 ( C) , 13 6 ( C) , 14 6 ( C) iii. Isotopes of chlorine : 35 17 ( Cl) , 37 17 ( Cl) Isobars: ✓ Atoms of different elements having same mass numbers and different atomic numbers are called as isobars. Example: 14 7 N and 14 6 C Isotones: ✓ Species having same number of neutrons are called isotones. Example: 3 1 H and 4 2 He Isoelectronic: ✓ Species having same number of electrons are called isoelectronic species. Example: Na + and Mg 2+ Cation: ✓ Species carrying positive charge is called cation. ✓ Cation is formed when a neutral atom looses one or more electrons. Example: Na + , K + , Mg 2+ Anion: ✓ Species carrying negative charge is called anion. ✓ Anion is formed when a neutral atom gains one or more electrons. ✓ Example: 2 C O F , , l − − − ✓ In Neutral atom ( A Z X ) : No. of protons = No. of electrons = Atomic No. ✓ In a Negative ion ( n − X ) : No. of electrons = Z + n ✓ In a Positive ion ( n + X ) : No. of electrons = Z – n Examples: I. Calculate the number of electrons, protons and neutrons in the following atom. 1. 3 − 31 15 P Ans: ✓ No. of potons = Z = 15 ✓ No. of electrons = Z + No. of negative charge = 15+3 = 18 ✓ No. of neutrons = A - Z = 16 2. 24 12 Mg Ans: ✓ No. of potons = Z = 12 ✓ No. of electrons = Z (for neutral atom) = 12 ✓ No. of neutrons = A - Z = 12 3. 40 18 Ar Ans: ✓ No. of potons = Z = 18 ✓ No. of electrons = Z (for neutral atom) = 18 ✓ No. of neutrons = A - Z = 22 4. 40 20 Ca Ans: ✓ No. of potons = Z = 20 ✓ No. of electrons = Z (for neutral atom) = 20 ✓ No. of neutrons = A - Z = 20 5. 2 + 88 38 Sr Ans: ✓ No. of potons = Z = 38 ✓ No. of electrons = Z – No. of positive charge = 38 – 2 = 36 ✓ No. of neutrons = A - Z = 50 II. The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. Assign the proper symbol to the species. Ans: 32 2 16 S − Exercise: 1. 7 Complete the table : Sl.No. Symbol Atomic number Mass Number Protons Neutrons Electrons 1. Na 11 12 2. Al 3+ 27 10 3. Cl - 18 18 4. Cu + 35 28 5. O 2 - 8 15 6. Ca 2+ 20 20 7. Br - 35 45 8. U 92 238 9. Cl 37 17 10. Na + 11 12 ANSWERS : Exercise : 1.1 1. CuCl 2 2. CuCl 3. Ba(NO 3 ) 2 4. FeSO 4 5. Fe 2 (SO 4 ) 3 6. (NH 4 ) 2 SO 4 7. Ca(HCO 3 ) 2 8. Al(OH) 3 9. Na 2 CO 3 10. Na 3 PO 4 11. MgCl 2 12. MgSO 4 13. ZnS 14. ZnSO 4 15. KNO 3 16. K 2 SO 4 17. KMnO 4 18. K 2 Cr 2 O 7 19. MgCO 3 20. (NH 4 ) 3 PO 4 21. NH 4 Cl 22. BaSO 4 23. BaCl 2 24. Ca(NO 3 ) 2 Exercise: 1.2 1. Cuprous oxide 2. Sodium sulphite 3. Potassium sulphate 4. Barium chloride 5. Ammonium nitrate 6. Calcium hydroxide 7. Lead nitrate 8. Aluminium chloride Exercise : 1.3 1. 2 2 3 2SO + O 2SO ⎯⎯ → 2. 2 2 2NO + O 2NO ⎯⎯ → 3. 3 2 2KClO 2KCl + 3O ⎯⎯ → 4. 3 2 2 2 2Zn(NO ) 2ZnO + 4NO + O ⎯⎯ → 5. 2 3 6Li + N 2Li N ⎯⎯ → 6. 2 3 2 3Mg + N Mg N ⎯⎯ → 7. 2 2 3 N + 3H 2NH ⎯⎯ → 8. 3 4 2 2Pb O 6PbO + O ⎯⎯ → 9. 2 2 3 4Al + 3O 2Al O ⎯⎯ → 10. 2 2 2 4HCl + O 2Cl + 2H O ⎯⎯ → 11. 2 3 2Fe + 3Cl 2FeCl ⎯⎯ → Excercise : 1.4 1. +6 2. +5 3. +3 4. +6 5. +4 6. +6 7. - 3 8. - 4 9. +5 10. +4 11. +5 12. +3 13. +5 Exercise : 1.5 Element Electronic configuration S 1s 2 2s 2 2p 6 3s 2 3p 4 Cl 1s 2 2s 2 2p 6 3s 2 3p 5 Ar 1s 2 2s 2 2p 6 3s 2 3p 6 K 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Ca 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Sc 1s 2 2s 2 2p 6 3s 2 3p 6 3d 1 4s 2 Ti 1s 2 2s 2 2p 6 3s 2 3p 6 3d 2 4s 2 V 1s 2 2s 2 2p 6 3s 2 3p 6 3d 3 4s 2 Cr 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s 1 Mn 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s 2 Fe 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 4s 2 Co 1s 2 2s 2 2p 6 3s 2 3p 6 3d 7 4s 2 Ni 1s 2 2s 2 2p 6 3s 2 3p 6 3d 8 4s 2 Cu 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 1 Zn 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 Exercise: 1.6 1. 2. 3. 4. C H H H CH CH C N H C H O C H H C C C H H H H 5. 6. 7. 8. N C N O H H H H 9. C H H H C C H OH H H H C H H H C OH O C H H H C C H OH H H C H H H C H H H C C C H H H C H OH H H C H H H C C H Exercise: 1. 7 Complete the table : Sl.No. Symbol Atomic number Mass Number Protons Neutrons Electrons 1. Na 11 23 11 12 11 2. Al 3+ 13 27 13 14 10 3. Cl - 17 35 17 18 18 4. Cu + 29 64 29 35 28 5. O 2 - 8 15 8 7 10 6. Ca 2+ 20 40 20 20 20 7. Br - 35 80 35 45 36 8. U 92 238 92 146 92 9. Cl 17 37 17 20 17 10. Na + 11 23 11 12 10