Alkaline Earth Metals
The metals in Group II of the periodic table are called the alkaline earth metals. They are:
Most of he alkaline earth metals are shiny and silvery white in color. They are lustrous, ductile, and malleable.
The alkaline earth metals have the high thermal and electrical conductivity.
Because of their reactivity, alkaline earth metals do not occur naturally in their elemental state.
They are called earth metals because their compounds were first found in plant remains in soil.
They are less reactive than alkali metals.
They react with water to form alkaline solutions. For example:.
- calcium + water calcium hydroxide + hydrogen
- 2 Ca + 2H2O 2 Ca(OH)2 + H2
Alkaline earth metals are reactive metals. The reactivity increases on moving down the Group from magnesium to barium. That means as their atomic numbers increase the furthur down they appear in the group, their reactivity increases.
This group lies in the s-block of the periodic table. Each alkaline earth metal atom has two valence electrons in its outermost shell (s-orbital). They are ready to give up those two electrons in electrovalent (ionic) bonds. This gives alkaline earth metals the largest atomic radii in their periods.
Alkaline earth metals have low electron affinities and low electronegativities.
They react with acids to form salts and hydrogen gas. For example:.
- magnesium + florine magnesium floride
- Mg (s) + F2 (g) MgF2 (s)
Alkaline earth metals react with halogens to form salts. For example:.
- magnesium + hydrochloric acid magnesium chloride + hydrogen
- Mg (s) + 2HCl (aq) MgCl2 (aq) + H2 (g)
Alkaline earth metals react with oxygen to form oxides or peroxides. The oxides of the alkaline earth metals are basic. For example:.
- magnesium + oxygen magnesium oxide
- 2Mg (s) + O2 (g) 2MgO (s)
Alkaline earth metals react with hydrogen to form hydrides. For example:.
- magnesium + hydrogen magnesium hydride
- Mg (s) + H2 (g) MgH2 (s)
Alkaline earth metals react with nitrogen to form nitrides. For example:.
- magnesium + nitrogen magnesium nitride
- 3Mg (s) + N2 (g) Mg3N2 (s)
Alkaline earth metals include radium is naturally radioactive element.