Alkalifémek

Alkalifémek, also known as alkali metals, are a group of chemical elements in the periodic table, specifically those in group 1. This group includes lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Alkalifémek are characterized by their single valence electron in the outermost shell, which makes them highly reactive. They are soft, silvery metals that tarnish quickly when exposed to air due to their reactivity with oxygen and moisture.

The reactivity of alkalifémek increases as you move down the group. Lithium, the least reactive, is used in batteries and as a reducing agent. Sodium, the most abundant alkali metal in the Earth's crust, is essential for biological functions and is used in various industrial applications. Potassium is crucial for plant growth and is used in fertilizers. Rubidium and cesium are less common but have specific uses, such as in atomic clocks and photoelectric cells. Francium, the most radioactive and least stable of the alkalifémek, is extremely rare and has no practical applications.

Alkalifémek react vigorously with water, producing hydrogen gas and the corresponding hydroxide. They also react with halogens to form salts. Due to their high reactivity, they are typically stored under oil to prevent contact with air and moisture. The study of alkalifémek is important in understanding the behavior of other elements and the principles of chemical bonding.