Question

30.
The incorrect order of negative electron gain enthalpy or electron gain enthalpy of the elements of
oxygen family in the periodic table is/are
A) O > S > Se B) S > O > Se C) S > Se > 0 D) Se > O >S​

Answer 1

Answer:

In a period, with the increase in atomic number, electron affinity becomes more negative due to the increase in the effective nuclear charge. In a group, it becomes less negative on moving from top to bottom.

N has positive electron affinity due to the extra stability of exactly half-filled p orbitals.

In case of F

−

ion and O

6−

ion, due to small size, the inter-electronic repulsion is higher. Hence, less energy is evolved in the formation of the ion.

Due to this, the orders (b) CI > F and (c) S > O is correct.

The orders a, b, c, and f are correct whereas the orders d and e are incorrect.

Hence, the correct option is B