Which of the following has the greatest polarizability?

Question

A) F
B) Br
C) Po
D) Pb

I picked C, because it has the largest atomic mass, and the polarizability is directly related to the atomic/molecular mass.

Yet somehow the answer is D.

The question is followed one.

Which has the smallest polarizability?
A) Si
B) S
C) Te
D) Bi

I picked Si, because it has the lowest atomic mass. Again, the answer is different. The correct answer is written as B.

What am I doing wrong?

Are the shells which the electrons occupy to be taken into account?

Answer 1

Your forgetting to take into account the atomic radii of the molecules. As you travel across a row in the periodic table of elements you will notice the atomic radii decreases, this is because of the fact the nucleus is gaining additional protons as a result valence orbital is drawn closer to the nucleus therefore making the atom less able to be polarized.