The charge of an atom before any electrons are transferred is zero.An atom as a whole is electrically neutral.
An atoms contains same number of electrons and protons. The charge of an electron and a proton is equal in magnitude but opposite in sign. The charge of a proton is 1.6 x 10⁻¹⁹C and the charge of an electron is -1.6 x 10⁻¹⁹C .Thus the charge of all the protons in an atoms is neutralized by the total charge of all the electrons.Thus an atom is electrically neutral.
when an atom loses electrons , it acquires a positive charge and when it gains electrons, it acquires a net charge.
