Knowra Calcium Calcium Calcium is a soft, reactive alkaline-earth metal with atomic number 20. It is abundant in minerals such as limestone and essential to living organisms.
Calcium ion : A calcium atom that has lost two electrons, giving it a 2+ charge. The ion is calcium’s prevalent form in water and the form cells use for signaling.
Atomic number : The number of protons in an atom’s nucleus, which identifies its chemical element. Calcium’s atomic number, 20, defines its elemental identity.
Portland cement : A hydraulic cement made chiefly from clinker produced by heating limestone and clay. Limestone supplies calcium compounds that become central phases in cement clinker.
Magnesium : A lightweight alkaline-earth metal with atomic number 12. Magnesium sits above calcium in Group 2 and is generally less reactive with water.
Calcium carbonate : A compound of calcium, carbon, and oxygen found in limestone, chalk, and shells. Calcium forms this widespread mineral compound through reactions with carbonate.
Electron shell : A region of atomic electrons grouped by energy around the nucleus. Calcium’s outer electron shell helps explain its tendency to form 2+ ions.
Lime (material) : Calcium-containing materials, especially quicklime and hydrated lime, used in construction and industry. Calcium oxide and hydroxide are used to make mortar and treat materials.
Strontium : A reactive alkaline-earth metal with atomic number 38. Strontium lies below calcium in Group 2 and is more reactive.
Calcium oxide : A white solid, also called quicklime, produced by heating calcium carbonate. Heating limestone converts its calcium carbonate into this reactive calcium compound.
Ionic bond : An electrostatic attraction between oppositely charged ions. Calcium’s compounds often form when calcium ions attract negatively charged ions.
Show all 22