What is a common chemical property of group 2 elements?

Group 2 elements, also known as the alkaline earth metals, exhibit the characteristic of losing two electrons to form +2 cations. This unique behavior is attributed to their electron configuration, where these elements have two valence electrons in their outermost shell. When they react, they tend to lose these two electrons to achieve a stable noble gas configuration, resulting in the formation of positively charged ions with a charge of +2.

For example, magnesium (Mg) will lose its two outermost electrons to become Mg²⁺. This property is fundamental in understanding the reactivity of alkaline earth metals, as they readily participate in chemical reactions to achieve stability. This loss of electrons underpins their ability to react with water, acids, and other nonmetals, forming various compounds that reflect their +2 oxidation state.

The other options do not accurately describe the behavior of group 2 elements: they do not gain electrons to form cations, they are not inert, and they do not inherently form compounds with a -2 charge since their common oxidation state is +2.