Question

in spite of having so many electrons why charge of an atom is zero

Answer 1

Because it has both electrons and protons ,that neautralizis its charge making it 0.
Hope it helps

Answer 2

the charge of atom is zero because as you would zoom and see in electron there are many elementary particle so according to me they make an zero charge and may be because of protons and electron make an fussion which makes neutrons which neutral and the atom gets zero charge