Question

STATEMENT-1 : The second ionisation energy of oxygen is greater than that of nitrogen.
STATEMENT-2 : The half filled p-orbitals cause greater stability.

• A. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1
• B. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
• C. STATEMENT-1 is True, STATEMENT-2 is False
• D. STATEMENT-1 is False, STATEMENT-2 is True

Answer 1

The correct option is A STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1

For $O^{+}$ ion, the electronic configuration is $1s^{2}2s^{2}2p^3$. It has stable, half filled subshell. It is difficult to remove an electron from this subshell and requires very high energy. Hence, oxygen has high second ionisation energy.
Note: The half filled p-orbitals cause greater stability.
For $N^{+}$ ion, the electronic configuration is $1s^{2}2s^{2}2p^2$. Removal of an electron from 2p subshell will require less energy.
Hence. the second ionisation energy of oxygen is greater than that of nitrogen.
Hence, STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1.