elektropositif

Elektropositif, or electropositive, describes the tendency of an element to donate electrons and form positive ions in chemical reactions and compounds. The term is used to contrast electronegativity, which measures an element’s tendency to attract electrons. In practice, electropositivity correlates with low ionization energy, high metallic character, and low electronegativity on scales such as the Pauling scale.

Electropositive elements are typically metals, especially the alkali metals (lithium, sodium, potassium, rubidium, cesium, francium) and alkaline earth metals (beryllium, magnesium, calcium, strontium, barium, radium). These elements readily lose electrons to form cations and show large atomic radii and relatively low first ionization energies. Some other metals also exhibit electropositive behavior to varying degrees, but the concept is most informative for the highly reactive alkali and alkaline earth metals.

In bonding, electropositive elements tend to form ionic bonds with more electronegative elements such as nonmetals and halogens. They often act as reducing agents, donating electrons to less electropositive species. The reactivity of electropositive metals increases down a group and with increasing access to lower oxidation states; they can readily react with water and oxygen, producing hydroxides and oxides and releasing hydrogen gas in some cases.

Note that in modern chemical literature, electropositivity is discussed less as a formal property and more in terms of electronegativity, metallic character, and standard reduction potentials. The concept remains useful for characterizing trends in reactivity and bonding among metals.