What group in the periodic table do alkali metals belong to?

Alkali metals are found in Group 1 of the periodic table. This group includes elements such as lithium, sodium, potassium, rubidium, cesium, and francium. The defining characteristic of alkali metals is that they have a single electron in their outermost shell, which makes them highly reactive, particularly with water and halogens. This group is known for its metallic properties, such as being soft and having low melting points compared to other metals. Their reactivity increases as you move down the group, which is attributed to the decreasing ionization energy needed to remove the outermost electron.

The incorrect options correspond to groups that have different elements with properties distinct from those of alkali metals. Group 2 contains alkaline earth metals, Group 17 consists of halogens, and Group 18 is made up of noble gases, all of which exhibit different chemical behaviors and electronic configurations.