Elements gain and lose electrons so that they have the same number of electrons as the noble gases.
• Metals → lose electrons and gain positive (+) charge to become more like their closest noble gas
• Nonmetals → gain electrons and have negative (-) charge to become more like their closest noble gas.
Group 1A metals Lose 1 e- +1 charge
Group 2A metals Lose 2 e- +2 charge
Group 3A metals Lose 3 e- +3 charge
Group 4A nonmetals typically do not gain or lose e- until Tin (Sn) and Lead (Pb)
Group 5A nonmetals Gain 3 e- -3 charge
Group 6A nonmetals Gain 2 e- -2 charge
Group 7A nonmetals Gain 1 e- -1 charge
Group 8A Noble Gases Complete Electrons
Write the correct chemical formula for the compounds formed from each pair of ions.
a. K+, S2−
b. Ca2+, O2−
c. Na+, O2−
d. Al3+, N3−
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