Which of the following statements about alkali metals is true?

they form 1+ and 2+ cations not negative

They are VERY reactive

To determine which statement about alkali metals is true, we need to analyze each statement and understand the properties of alkali metals.

1. Alkali metals have full valence shells: This statement is false. Alkali metals have one valence electron, which means their valence shells are not full.

2. Alkali metals form 1+ cations: This statement is true. Alkali metals have a tendency to lose their single valence electron to achieve a stable electron configuration similar to the nearest noble gas. As a result, they form cations with a +1 charge.

3. Alkali metals are very reactive: This statement is true. Alkali metals are highly reactive due to the low ionization energy required to remove their valence electron. They readily react with water, oxygen, and other elements to form compounds.

4. Alkali metals form 2+ cations: This statement is false. Alkali metals actually form 1+ cations by losing their single valence electron.

Therefore, the correct statement is: "Alkali metals form 1+ cations."

The correct statement about alkali metals is that they are very reactive.