Why does oxygen show anomalous behaviour in its group ?

Why does Nitrogen show anomalous behaviour in its group ?

Why does fluoriue show anomalous behaviour in its group ?

(i) why are halogens strong oxidising agents ? (ii) Why oxygen shows anomalous behaviour from rest of members of its family ? (iii) Ammonia acts as a good complexing agent. Explain.

Why lithium shows anomalous behaviour ?

Discuss the anomalous behaviour of nitrogen.