Question

Explain why the atomic radius of oxygen is slightly more than that of nitrogen.

Answer 1

When moving along a period, the atomic radius is supposed to decrease. However oxygen has slightly higher atomic radius than nitrogen. This is because nitrogen has an electronic configuration $2p^3$ having its orbittal half filled and hence there is less repulsion between the electrons. Oxygen, however, has an electronic configuration of $2p^4$, having one paired electrons in one of its orbittals. This leads to inter-electronic repulsion and thus increases the atomic radius slightly