Question

Oxygen generally exhibits an oxidation state of $-2$ only while the other members of the group show oxidation states of $+2,+4$ and $+6$ also - explain.

Answer 1

oxygen generally exhibits an oxidation state of -2 only while the other members of the oxidation states of group show oxidation state of +2, +4 and +6 because it is highly electro-negative. Oxygen is the 2nd most electro-negative element after Flourine. So when oxygen combines with flourine it shows positive oxidation states only. While other elements of the oxygen group show +2 and +4 because they are less electro-negative like oxygen and fluorine and when they combine with oxygen, fluorine, and chlorine they show positive oxidation states.

Oxygen is the most electronegative element after fluorine. For OF2 the oxidation number is +2 whereas for O2F2 it is +1 because fluorine is the more electronegative element and so it is assigned oxidation number of -1. Other elements of this family show +2, +4 or +6 oxidation state because they are not as electronegative as oxygen. Due to an increase in the number of electron shells down the group electronegativity decreases.