Group 2

• Group 2 elements, known as alkaline-earth metals, include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
• These elements are s-block elements as their outer electrons are in s-orbitals.
• Alkaline-earth metals have two electrons in their outermost s orbital. Due to this characteristic, they have an oxidation state of +2 in most of their compounds.
• Group 2 elements exhibit metallic properties such as shiny appearance, good conductors of heat and electricity, and malleability.
• Alkaline-earth metals are less reactive than the Group 1 metals (alkali metals) yet more reactive than most other elements. Reactivity increases down the group as the atomic size increases and ionisation energy decreases.
• Compounds formed by Group 2 elements are typically white solids that are insoluble in water.
• When reacted with oxygen, the metals form oxides: for example, 2Mg + O2 → 2MgO.
• With water, these elements form hydroxides and release hydrogen gas: for instance, Mg + 2H2O → Mg(OH)2 + H2.
• Beryllium is unique among the Group 2 metals because it does not react directly with water or any compound containing the hydroxide (OH) ion.
• Each Group 2 element forms one stable, naturally occurring isotope, except for Beryllium and Radium.
• The atomic and ionic radii of Group 2 elements increase down the group; this is due to an increased number of electron shells.
• The first ionisation energy decreases down the group because the outermost electrons are further from the nucleus and therefore less tightly bound.
• Solubility of hydroxides and sulphates in water varies down the group. Hydroxides become more soluble while sulphates become less soluble.
• Group 2 elements and their compounds are widely used in industry. Magnesium and its alloys are used in aircraft, automobile and electronics because of their light weight and strength. Lime (CaO), a product of Calcium, is used in agriculture to neutralise acidic soils.