Question

Why is decrease in electronegativity less from Phosphorus to Bismuth and the same for Antimony and Bismuth?

Answer 1

As we know electronegativity depends on the size of an atom. After P all the elements in group-15 are post transition element. So the trend of increase in size from As to Bi is same and the strength of decreasing electronegativity is also same. But due to poor shielding of d-electrons, there is less increase in size from P to As , Sb and Bi hence less decrease in electronegativity is observed.