Question

Why an atom is called electrically neutral?

Answer 1

Atoms are electrically neutral because they contain equal numbers of protons and electrons.An atomic nucleus is made of two kinds of particles, protons and neutrons. A proton has a positive charge and a neutron is electrically neutral. The atomic nucleus is surrounded by negatively charged particles called electrons.
A proton with positive charge is equal in magnitude to the negative charge of an electron, hence atom is neutral.