PERIODIC CLASSIFICATION OF ELEMENTS
Each of the questions given below consists of two statements, an assertion (A) and reason (R).
Select the number corresponding to the appropriate alternative as follows
(1) If both A and R are true and R is the correct explanation of A, then mark 1
(2) If both A and R are true but R is not the correct explanation of A, then mark 2
(3) If A is true but R is false, then mark 3
(4) If both A and R are false, then mark 4
1. A. Chlorine has higher EA than that of fluorine.
R. Fluorine is stronger oxidising agent than chlorine.
2. A. Metallic character increases on going down a group from top to bottom.
R. Ionization energy decreases on going down a group from top to bottom.
3. A. Mg2+ ion is smaller in size than F–.
R. Mg2+ has less number of electrons than F–.
4. A. All the elements belonging to d-block are metals.
R. Additional electrons are repelled more effectively by 3p electorns in Cl atom than by 2p electrons in F atom.
5. A. Beryllium has greater IE than boron.
R. Boron has higher EA than beryllium.
6. A. Third IE of magnesium is greater than of aluminium.
R. Mg2+ ion has stable noble gas configuration.
ANSWERS
PERIODIC CLASSIFICATION OF ELEMENTS
1. (2)
2. (1)
3. (3)
4. (3)
5. (2)
6. (1)
CHEMICAL BONDING
1. A. The melting point of LiCl is lower than that of NaCl.
R. LiCl has predominantly covalent character whereas NaCl is predominantly ionic.
2. A. Pressing of two ice cube over each other cause their unificatin.
R. Convalent bonds are formed between the water molecules at the interface.
3. A. XeF2 is a linear molecule.
R. Xe atom assu,pes sp hybrid state in XeF2.
4. A. The bond angle of directed bonds arount S in H2S is 92º.
R. Resonating forms go on changing into one another rapidly due to change in electronic arrangment.
5. A. O2 molecules in paramagnetic in nature.
R. O2 molecule contains two unpaired electrons in pi antibonding orbitals.
6. A. All carbon-carbon bonds in benzene molecule are equally strong.
R. Benzene molecule is resonance stabilised.
7. A. In F2C = C = CF2, the central atom is sphybridised.
R. The F atoms on carbon 1 and 3 in F2C = C = CF2 lie on perpendicular planes.
8. A. A molecule with formula MX3 may or many not have trigonal planar geometry.
R. Geometry of MX3 depends upon the number of lone pair and bond pairs around M.
9. A. Chlorate ion is pyramidal in shape.
R. Hybrid state of chlorine in chlorate ion is sp3.
ANSWERS
CHEMICAL BONDING
1. (1)
2. (3)
3. (3)
4. (2)
5. (1)
6. (2)
7. (2)
8. (1)
9. (1)
10. (1)
STATES OF MATTER (GASES)
1. A. The product of pressure and volume for afixed amount of gas is equal to a constant represented by RT.
R. At constant temperature, for a fixed amount of a gas, pressure is inversely proportional to volume.
2. A. The mixture of ideal gases A and B on their liquefaction gives ideal solution of A and B.
R. The ideal gases cannot be liquefied.
3. A. The value of van der Waal constant b is higher for N2 than for NH3.
R. NH3 molecules are associated with H–bonds.
4. A. At a particular temperature , the value of mean free path increases with decreases in pressure.
R. All the gas molecules at a particular temperature possess same speed.
5. A. The abrupt expansion of the compressed gas always causes heating effect.
R. The expansion causes release of energy by the gaseous system.
6. A. Compressibility factor of ideal gas is zero.
R. The molecules of ideal gas are volumeless points.
7. A. Dry air is heavier than moist air.
R. The vapour density of moist air lies between 9 and 14.4.
8. A. Rate of diffusion of N2 is more than that of CO2.
R. Both N2 and CO2 have same value of van der Waal constant b.
9. A. Heat capacity of a diatomic gas is higher than that of monoatomic gas.
R. Monoatomic gases are non-polar in nature.
10. A. Noble gases can be liquified.
R. Attractive forces can exist between nonpolar molecules.
11. A. Noble gases have highest ionization energies in their respective periods.
R. Noble gas have stable electronic configuration.
12. A. The mixture of ideal gases A and B on their liquefaction gives ideal solution of A and B.
R. The ideal gases cannot be liquefied.
13. A. The value of van der Waal constant b is higher for N2 than for NH3.
R. NH3 molecules are associated with H–bonds.
14. A. At a particular temperature , the value of mean free path increases with decreases in pressure.
R. All the gas molecules at a particular temperature possess same speed.
15. A. Rate of diffusion of N2 is more than that of CO2.
R. Both N2 and CO2 have same value of van der Waal constant b.
16. A. Noble gases can be liquified.
R. Attractive forces can exist between nonpolar molecules.
ANSWERS
STATES OF MATTER (GASES)
1. (4)
2. (4)
3. (2)
4. (3)
5. (4)
6. (3)
7. (3)
8. (4)
9. (2)
10. (1)
11. (1)
12. (4)
13. (2)
14. (3)
15. (4)
16. (1)
