Question

First member of each group of representative elements (i.e., s and p-block elements) shows anomalous behavior. Illustrate with two examples.

Answer 1

Anomalous Properties of Second Period Elements: Their anomalous behavior is attributed to their small size, large charge/radius ratio, high electronegativity and non-availability of d-orbitals in their valence shell. The first member of each group of p-Block elements displays greater ability to form $p_{\pi }-p_{\pi }$ multiple bonds to itself (e.g., $C=C,C=C,O=O,N=N$) and to other second period elements (e.g., $C=O,C=N,N=O$ compared to subsequent members of the group.