In any given atom, the number of protons in the nucleus of an atom equals to the number of electrons in the energy level. The protons are positively charged while the electrons are negatively charged. For example, a sodium atom has 11p ,11e and 12n , the neutrons have no charge. The protons therefore has a charge of +11 and the electrons a total charge of -11
-11+11= 0 , the opposite equal charge cancels each other therefore the final net charge is zero .
Now try proving that chlorine atom with atomic number 17 is neutral .
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