Give reasons for the following :
(i) Covalent bonds are directional while ionic bonds are non-directional.
(ii) Water molecule has bent structure whereas carbon dioxide molecule is linear.
(iii) Etyne molecule is linear.

Explanation

(i) In covalent bond, the shared pair of electrons is localized between the two atoms and this gives a
directional character . In ionic bonds, an ion is surrouneded by oppositely charged ions in any direction and
the oppositely charged ions are held together by electrostatic forces. Hence, they are non-directional.
(ii) In `H_(2)O,""_(8)O= 1s^(2) underbrace(2s^(2) 2p_(x)^(2) 2p_(y)^(1) 2p_(z)^(1)) ` O-atom is `sp^(3) ` hybridized . Two hybrid orbitals are half-filled and
two are occupied by lone pairs of electrons . Half-filled orbitals overlap with half-filled orbitals of H-atoms
Hence, it has a bent structure .

In `CO_(2), ""_(6)C = 1s^(2) underbrace(2s^(1) 2p_(x)^(1)) 2p_(y)^(1) 2p_(z)^(1)` (excited state ) and `._(8)O = 1s^(2) 2s^(2) 2p_(x)^(2) 2p_(x)^(2)2p_(y)^(1) 2p_(z)^(1)`
C is sp hybridized forming two sp hybrid orbitals nad two half-filled 2p orbitals are left umhybridized . The
overlappings take place as follows :
.