Charges of a chemical species

In a chemical species the charges are determined from →       Lewis structures of atoms. Method: The two electrons of each bond are distributed equally between the two atoms they connect, then we compare them to the Lewis structure. For example:

Attribution of the electrons:

Comparison with Lewis structures:

Correct charges:

If the dative bonds are represented by arrows, we write only the global charge by exposing it behind the molecule . For example:

Dative bonds (the red electrons are "supplied" only by the chlorine pairs):

Attribution of the electrons:

Correct charges:

Dative bonds represented by arrows (two - charges and two + charges omitted):

This mode of representation is to be discouraged in the study of the mechanisms, since it conceals the real charges!