Question

With respect to `H-H`, `O-H`, `N-N`, `C-O`, `C-H`, `N-H`, and `C-C` bonds, how can you classify each bond in terms of covalency, and polarity?

Answer 1

Pure covalent: `H-H`, `N-N`, `C-C`, and `C-H`.

Polar covalent: `O-H`, `N-H`. `C-O` bonds have some degree of polarity.

There are no ionic bonds presented.

Explanation:

Differences in electronegativities are sometimes presented as a criterion for the covalency/polar covalency of given bonds. By this criterion, element-element bonds have zero electronegativity difference.

For a `C-H` bond, (I forget the numbers), the electronegativity difference is non-zero, but such bonds would reasonably be regarded as covalent, with very marginal polarity; ethereal bonds (`C-O`) likewise. `O-H`, and `N-H` bonds would have the greatest degree of polarity, and this is manifested by the higher boiling points of water and ammonia with respect to comparable molecules (attributable to intermolecular hydrogen bonding).