I .
One way the periodic table is organized is in vertical columns
known as groups. These groups are further organized into A and
B groups. The group 7A indicates:
0
7 valence electrons, 1 - ionic charge, nonmetal,
halogens
1 valence electron, 1 - ionic charge, metals, alkali
metals
8 valence electrons, metals, no ion formation, noble
gases
7 valence electrons, 7 + ionic charge, nonmetals,
halogens