Among the following bonds, which would be the least polar? Electronegativity values are: Na = 0.9, O = 3.5, F = 4.0, Cl = 3.0, Br = 2.8, I = 2.5

e. Na_I

Explanation:

a.  Na–O

b.  Na–F

c.  Na–Cl

d.  Na–Br

e.  Na–I

Bond polarity can be calculated, examining the Pauling scale electronegativity values of the two atoms. The difference between these values will determine the predominant type of bond between the respective atoms.

Therefore, Na-I would be least polar bond. (The difference in the electronegativies of the two atom is least)

that's what i got you can count the number of atoms