Question

(I) CuCl is more covalent than NaCl. Give reason? 

(II) Draw and explain the molecular orbital diagram of Boron molecule?

Answer 1

(I) 

1. Cations having ns² np⁶ nd¹⁰ configuration show greater polarising power than the cations with ns² np⁶ configuration. Hence they show greater covalent character.

2. CuCl is more covalent than NaCl. As compared to Na⁺ (1.13Å), Cu (0.6Å) is small and has 3s²3p⁶3d¹⁰ configuration.

3. Electronic configuration of Cu⁺ : [Ar] 3s² 3p⁶ 3d¹⁰ 

Electronic configuration of Na⁺: [He] 2s² 2p⁶ So CuCl is more covalent than NaCl.

(II)

1. Electronic configuration of B = 1s² 2s² 2p³ 

2. Electronic configuration of B₂ = 

3. Bond order = \(\frac{N_b - N_a} {2}\) = \(\frac{6 - 4}{2}\) = 1

4. B₂ molecule has two unpaired electrons hence it is paramagnetic.