Which of the following atoms should have the greatest polarizability?

F

Br

Po

Pb

He

Pb has the greatest polarizability

Explanation:

Step 1: Data given

The atom that is the least electronegative AND the largest radius is the most polarizable.

The least electronegative atom is lead (Pb)

⇒ electronegativity increases from left to right (in the same period)

⇒ electronegativity decreases going downwards (in the same group)

The atoms with largest radius are Po (190 pm) and Pb (180 pm)

This means the two elements with the highest polarizability in this list are Pb and Po.

Since Po has 84 electrons compared to 81 electrons for lead, means that the electrons occupy a greater volume in Pb.

Pb has the greatest polarizability since it's electrons are the farthest away from the nucleus and are thus less tightly bound, making them easier to shift around.