↪ Alkaline earth metals Beryllium(Be), Magnesium(Mg), Calcium(Ca), Strontium(Sr), Barium(Ba) and Radium(Ra) belong to ⅡA group in the s-block of periodic table.
↪ These elements are called alkaline earth metal because:
i. Their oxides form alkali with water.
ii. Their oxides exist in earth crust.
General Characteristics of alkaline earth metals
⁕ Physical Properties
1. Physical state
↪ They are soft metal but harder than alkali metals.
↪ They are silvery white but get tarnished in air.
3. Oxidation state
↪ These elements exhibit +2 oxidation states in combine state.
4. Atomic and ionic radii
↪ Atomic radii and ionic radii are fairly large though smaller than that of corresponding alkali metals.
5. Ionization energy
↪ Alkaline earth metals have fairly low ionization energy however higher than that of alkali metals.
6. Reducing nature
↪ They have high tendency to lose electron. So, they are strong reducing agent but weaker than alkali metals.
↪ They are low electronegative elements but higher than alkali metals.
↪ They are excellent conductor of electricity.
9. Melting point and boiling point
↪ Alkaline earth metals have low melting and boiling point in period but higher than alkali metals.
10. Flame color
↪ Except Be and Mg, alkaline earth metals impart characteristics color in the flame of Bunsen burner.
⁕ Chemical Properties
1. Action with air
↪ Alkali metals react with moist air to form oxides, hydroxides and carbonate due to which they get tarnished.
2. Action with water
↪ Be doesn’t react with water, Mg reacts with hot water while Ca, Sr and Ba react with cold water rapidly liberating hydrogen gas.
3. Action with hydrogen
↪ Ca, Sr and Ba react with hydrogen at elevated temperature to form metal hydrides.
4. Action with Nitrogen
↪ Alkaline earth metals react with nitrogen at elevated temperature to form metal nitride.
5. Action with halogen
↪ Alkaline earth metals react with halogens to form corresponding halides.