Question

consider the following element combinations. Classify the bonds formed between each pair as ionic, polar covalent, or non polar covalent. S-S, Ba-O, Al-N, O-F, S-Cl, I-I, P-I, Cs-Cl

Answer 1

Bonds between atoms of the same kind are covalent bonds (or non polar covalent bonds).

Any other covalent bond formed between two atoms of different kinds would be partly or purely polar in nature.

If the electronegativity difference between the two atoms is very high (like a metal and a non-metal) the bond will be ionic.

Hence, if electronegativity difference is

0 - 0.4 Covalent

0.5 - 1.7 Polar Covalent

More than 1.7 Ionic

S-S non-polar covalent

Ba-O ionic

electronegativityof Ba = 0.9

electronegativity of O = 3.5

electronegativity difference = 3.5 - 0.9 = 2.4

Al-N   polar covalent

electronegativityof Al = 1.5

electronegativity of N = 3.0

electronegativity difference = 3.5 - 1.5 = 1.5

O-F Polar covalent

electronegativityof O = 3.0

electronegativity of F = 4.0

electronegativity difference = 4.0 - 3.0 = 1.0

S-Cl polar covalent

electronegativity of S = 2.5

electronegativity of Cl = 3.0

electronegativity difference = 3.0 - 2.5 = 0.5

I-I non-polar covalent

P-I, non polar covalent

electronegativity of P = 2.1

electronegativity of l = 2.50

electronegativity difference = 2.5 - 2.1 = 0.4

Cs-Cl ionic

electronegativity of Cs = 0.7

electronegativity of Cl = 3.0

electronegativity difference = 3.0 - 0.7 = 2.3