Which oxidation state is typical for Group 1 elements in compounds?

• A. -1
• B. +2
• C. 0
• D. +1

Answer: (D)

Group 1 elements in compounds almost always lose one electron to form a +1 ion. They have just one valence electron, and removing it gives a stable noble-gas configuration, so they typically exist as M+ in salts and similar compounds. For example, NaCl, Li2O, and KBr all feature the alkali metal with a +1 charge. The elemental state is 0, which occurs only when the element isn’t bonded. A negative oxidation state would require gaining electrons, which isn’t typical for these metals, and a +2 state would require removing a second electron, which is energetically unlikely for Group 1. So the common oxidation state in compounds is +1.