The elements that has the maximum tendency to show the inert pair effect is

Options

A. `Bi`
B. `Sb`
C. `As`
D. `N`

Answer

1

Explanation

All the element of group `15` have five electrons in their valence shell they exhibits a highest oxidation state of `+5` by using all five electrons in forming bonds. As one goes down , the tendency of the pairs of ns electrons to remain inert (inert pair effect) increases and only np electrons are used in bonding ,resulting in an oxidation state of `+3` The stability of `+3` state relative to the `+5` state thus increases on moving down the group.
Arsenic and antimony (`V`) oxides can be obtained by oxidation of the element with concentrated nitiric acids:
`2Sb(s)+10HNO_(3)(a.q.)rarr Sb_(2)O_(5)(s)+5H_(2)O(l)+10NO_(2)(g)`
Both the oxides are unstable with respect to the `3`-valent state , decomposing into the `3`- valent oxide and oxygen occurring on gentle heating:
`2As_(2)O_(5)(s)rarrAs_(4)O_(6)(s)+2O_(2)(g)`
It is possible that `Bi(V)`oxide exists,although it has never been obtained in a pure form.In the view of the instability of the `5`- valent oxides of `As` and `Sb` to mind heating and the increased metallic character of `Bi`, it would be expected to be very unstable with respect to `Bi(III)` oxide.
Thus `N` showes the least tendency to show the inert pair effect while `Bi` shows the most tendency to exhibit inert pair effect.