Explanation:
It is known that in order to determine a compound to be ionic, polar, covalent or non-polar covalent it is necessary to determine the electronegativity difference of the combining atoms.
So, when electronegativity difference is from 0.0 to 0.4 then bond formed between the two atoms is non-polar covalent in nature.
When electronegativity difference is greater than 0.4 and less than 1.8 then bond between the two atoms is a polar covalent bond.
When electronegativity difference is 1.8 or greater than the bond formed is ionic in nature.
Electronegativity difference of the given molecules is as follows.
Si-O = (1.90 - 3.44) = 1.54
K-Cl = (0.82 - 3.16) = 2.34
S-F = (2.58 - 3.98) = 1.4
P-Br = (2.19 - 2.96) = 0.77
Li-O = (0.98 - 3.44) = 2.46
N-P = (3.04 - 2.19) = 0.85
Therefore, given compounds are classified as follows.
Si-O, S-F, P-Br, and N-P all have a polar covalent bond. Whereas K-Cl and Li-O are ionic in nature.