For an atom to have a balanced charged, the number of protons shall be equal to the number of electrons of an atom. proton is the positive part of an atom whereas electrons are the negative part of an atom. Only if the number of protons will be equal to the number of electron, the atom will be able to be neutral.
If the number of electron will be more, then the atom will be negative. If the number of electron will be less, then the atom will be positive.
