How are alkali earth metals classified in the periodic table?

Alkali earth metals are classified in Group 2 of the periodic table. This group consists of elements such as beryllium, magnesium, calcium, strontium, barium, and radium. These metals are characterized by having two electrons in their outermost electron shell, which they tend to lose easily during chemical reactions, resulting in the formation of cations with a +2 charge.

The properties of alkali earth metals include being shiny, silvery-white in color, and possessing relatively low densities and melting points compared to other metals. They are also reactive, though less so than the alkali metals of Group 1. Their reactivity increases down the group, making elements like barium and radium more reactive than beryllium.

In contrast, the other provided groups do not contain alkali earth metals. Group 1 consists of alkali metals, Group 13 includes elements such as aluminum, and Group 18 contains noble gases, which are inert and do not exhibit the same chemical reactivity as the alkali earth metals. Therefore, the classification of alkali earth metals as Group 2 is essential for understanding their chemical behavior and properties.