Q11Multiple choice
The formation of the oxide ion, O2– (g), from oxygen atom requires first an exothermic and then an endothermic step as shown below: V –1 O (g) + e– → O– (g) ; ∆ H = – 141 kJ mol V –1 O – (g) + e– → O2– (g); ∆ H = + 780 kJ mol 2– Thus process of formation of O in gas phase is unfavourable even though 2– O is isoelectronic with neon. It is due to the fact that,
- (i)oxygen is more electronegative.
- (ii)addition of electron in oxygen results in larger size of the ion.
- (iii)electron repulsion outweighs the stability gained by achieving noble gas configuration. –
- (iv)O ion has comparatively smaller size than oxygen atom.
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(iii) electron repulsion outweighs the stability gained by achieving noble gas configuration. –
(i) oxygen is more electronegative.
(ii) addition of electron in oxygen results in larger size of the ion.
(iv) O ion has comparatively smaller size than oxygen atom.