Which pair of bonds is more polar: P-Br and P-Cl?

1 Answer
May 31, 2018

Answer:

The #P–Cl# bond is more polar.

Explanation:

A polar bond is basically a bond where electrons are more drawn to one atom over the other atom.

That one atom will have a greater electronegativity, which means that it has a greater tendency to hog electrons in a bond.

When comparing two different polar bonds—two bonds that already have an uneven distribution of electrons—the one with the greater difference in electronegativity will be more polar.

This is because, as the electronegativity difference gets greater, electrons will spend more and more amounts of time with that more electronegative atom.

So, with that being said, here's the positions of #P#, #Cl#, and #Br# on a periodic table which shows electronegativity values:

Ptable

Electronegativity differences are:

  • #3.16-2.19=0.97# for a #P–Cl# bond.
  • #2.96-2.19=0.77# for a #P–Br# bond.

So, the #P–Cl# bond would be more polar since the electronegativity difference is higher.