Question

why does ionic character of trihalides of group 15 increase down the group?

why are trihalides of nitrogen the least stable among all the othere elements of group 15?

Answer 1

On moving down in group 15, the electronegativity of elements decreases and metallic character increases due to which the difference between the electronegativities of group 15 element and halogen atom increases and thus the ionic character of trihalides of group 15 increases down the group.

The trihalides of nitrogen the least stable among all the other elements of group 15 due small size of nitrogen atom.The difference between the small nitrogen atom and large halogen atom makes the bond between nitrogen and halogen atom weak due to which the stability of trihalides of nitrogen is less.