Assertion (A) : First ionisation energy of $O^{+} (g)$ is greater than that of N(g) but the first ionisation energy of $N^{+}$ (g) less than N(g).
Reason (R) : It is easier to remove the fourth 2p electron from oxygen than it is to remove 2p electron from nitrogen .

Question

Assertion (A) : First ionisation energy of $O^{+} (g)$ is greater than that of N(g) but the first ionisation energy of $N^{+}$ (g) less than N(g).

Reason (R) : It is easier to remove the fourth 2p electron from oxygen than it is to remove 2p electron from nitrogen .

TestHub · Accepted Answer

The first ionization energy of O⁺(g) is less than N(g) because O⁺ has a 2p³ configuration (half-filled, stable), while N has 2p³ (half-filled, stable). Removing an electron from O⁺ disrupts this stability less than from N. The first ionization energy of N⁺(g) is less than N(g) because N⁺ has a 2p² configuration, which is less stable than N's 2p³ configuration. Therefore, Assertion (A) is false. Reason (R) is true as it is easier to remove the fourth 2p electron from oxygen (making it 2p³) than a 2p electron from nitrogen (making it 2p²).

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