Calculate the number of protons neutrons , electrons and neutrons of calcium ion of CaCl2?
The ionic charge tells the number of electrons gained or lost. Since electrons are negative, adding an electron will make the ion have a negative charge, and losing electrons will make for a positively charged ion. In CaCl2 Ca is in ion form. A calcium(II) ion, Ca2+, has 20 protons and 18 electrons because it has lost two (to give it the +2 charge). p( Ca2+) = 20 e ( Ca2+) =20 - 2 = 18 n( Ca2+) = Ar ( Ca) - p( Ca2+) n( Ca2+) = 40 - 20 = 20