Barium is an alkaline earth metal. This article explains the defining characteristics of alkaline earth metals and how barium aligns with this classification.
Defining Alkaline Earth Metals
Alkaline earth metals are six elements in Group 2 of the periodic table: beryllium, magnesium, calcium, strontium, barium, and radium. They share common traits due to having two valence electrons in their outermost electron shell.
Elements in this group readily lose these two valence electrons to achieve a stable electron configuration, forming ions with a +2 charge. This tendency makes them highly reactive, although less reactive than alkali metals. Due to their high reactivity, they are rarely found as pure elements in nature, instead existing in compounds with other elements.
These metals appear silvery-white with a lustrous appearance when freshly cut. They are soft and possess low densities, though harder and denser than alkali metals. Alkaline earth metals also have high melting and boiling points and are good conductors of electricity.
Chemically, alkaline earth metals form strong bases when their oxides interact with water, contributing to their “alkaline” designation. They also react with halogens to form ionic compounds and with acids to release hydrogen gas. They react with water to produce hydrogen gas and their respective hydroxides.
Barium’s Classification and Properties
Barium is classified as an alkaline earth metal, in Group 2 of the periodic table with an atomic number of 56. It features two valence electrons in its outermost shell.
Barium readily loses these two valence electrons to form a stable Ba²⁺ ion. In its pure form, barium is a soft, silvery-white metal that tarnishes quickly upon exposure to air due to its reactivity, forming barium oxide.
Barium reacts with water to produce barium hydroxide and hydrogen gas. It forms compounds with halogens and reacts with acids. A distinctive property of barium is its ability to form insoluble sulfates, such as barium sulfate (BaSO₄).
Barium sulfate occurs naturally as the mineral barite and is insoluble in water, a property utilized in various applications. This insolubility is important because, while many soluble barium compounds are toxic, barium sulfate’s low solubility allows its safe use in medical imaging procedures. These shared electronic and chemical behaviors establish barium’s place within the alkaline earth metal family.