Which periodic group forms +1 ; +2 and -1 ions?

1 Answer
Mar 29, 2016

Respectively, #"Group 1"#, #"Group 2"#, and #"Group 17"#.

Explanation:

#"Group 1"# metals, the alkali metals, have the 1 valence electron, and thus form #M^+# ions when oxidized. #"Group 2"# metals, the alkaline earth metals, have 2 valence electrons, and thus form #M^(2+)# ions. The halogens, #"Group 17"#, reach a full valence shell upon reduction, and thus form #X^-# ions.