Leelismetallid

Leelismetallid, also known as alkali metals, are a group of chemical elements found in Group 1 of the periodic table. This group includes lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These elements are characterized by their high reactivity, particularly with water and halogens, and their tendency to lose their single valence electron to form positive ions with a +1 charge.

The alkali metals are soft, shiny, and have low melting and boiling points compared to other metals. They are never found in their pure form in nature due to their extreme reactivity; instead, they exist in compounds like salts and oxides. Lithium is the least reactive and has the lowest density among them. Sodium is commonly found in table salt (sodium chloride) and is essential for many biological processes. Potassium is also vital for living organisms, playing a role in nerve function and fluid balance. Rubidium and cesium are even more reactive than sodium and potassium, with cesium being the most reactive alkali metal and the most electropositive element. Francium is a rare, radioactive element with a very short half-life, making its chemical properties difficult to study extensively. Their reactivity and tendency to readily form ionic compounds make them important in various industrial applications, including batteries, soaps, and fireworks.