Question

charge of an atom be if it has six protons and six electrons

Answer 1

protons have a positive charge

electrons have a negative charge

the magnitude of the charges of a proton and an electron are the same. it's just the sign that is different.

Charge is additive, so if there are equal numbers of positive and negative charges all of the same magnitude, what is the overall charge?

Answer 2

The net charge is zero. Because the electrons and protons are evenly numbered.