Question

what is the charge of a sulfide ion ?

Answer 1

sulfide is S^2-

Answer 2

Charge of an ion depends upon the number of valence electrons it requires to achieve an octet.
Sulphide has received 2 electrons to complete its valence shell.
Thus, the charge of a sulphide ion will be 2- ...
A trick can be used to identify the charge...
Generally, if the suffix of the ion is -ide, its charge will be 2-
If the suffix is -ite, its charge will be 3-

Hope this helps...