Protons, neutrons, and electrons are subatomic particles present in an atom. The number of protons and electrons in a neutral atom is equal. Protons have a positive while electrons have a negative charge and they cancel the effect of each other. Neutrons are neutral. That is why atoms are electrically neutral.

For instance, sodium (Na) atom has 11 electrons and 11 protons,

Charge on 11 protons  =  11 x (+ 1.602 x 10-19) = +1.76 x 10-18

Charge on 11 electrons =  11 x (- 1.602 x 10-19) = – 1.76 x 10-18

The net charge on an atom is the sum of these charges, which is zero. Hence, the sodium (Na) atom is electrically neutral.

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