Question

Account for the following : 
Acidic character decreases from N₂O₃ to Bi₂O₃ in group 15.

Answer 1

Acidic character of oxides of group 15 elements decreases and basicity increases down the group.
As we move down the group, the atomic size increases, electronegativity decreases and metallic character increases. Oxides of Nitrogen and phosphorous are acidic whereas those of As and Sb are amphoteric and that of Bismuth is basic.