Question

Which pair of atoms will likely form a polar covalent bond?

Question 5 options:

	Magnesium and Oxygen
	Oxygen and Sulfur
	Carbon and Sulfur
	Carbon and Carbon

Answer 1

Answer : Oxygen & Sulfur

You can determine which pair will form polar covalent bond based on the electronegativity difference. Electronegativity is the ability of the atom to attract the bond pair of electrons towards it. If one atom is highly electronegative compared to other atom in the bond that electrons will be attracted more towards the highly electronegative atom. This will make the bond polar.

If the difference is between 0.0-0.3 – bond is non polar covalent

If the difference is between 0.4-1.7 – bond is polar covalent

If the difference is greater than 1.7 - bond is ionic

Electronegativity of Magnesium = 1.31

Electronegativity of Oxygen = 3.44

Electronegativity of Sulfur = 2.58

Electronegativity of Carbon = 2.55

1) Electronegativity difference between Magnesium & Oxygen = 3.44-1.31 = 2.13

This bond is ionic.

2) Electronegativity difference between Oxygen & Sulfur = 3.44 – 2.58 = 0.86

This bond is polar covalent

3) Electronegativity difference between Carbon & Sulfur = 2.58 -2.55 = 0.03

This bond is non polar covalent.

4) Electronegativity difference between Carbon & Carbon = 2.55 -2.55 = 0

This bond is non polar covalent.