| Reactions of Calcium |
 Reactions with water |
| Calcium reacts slowly with water to form calcium hydroxide and hydrogen gas. The calcium metal sinks in water and after an hour or so bubbles of hydrogen are evident, stuck to the surface of the metal.
|
Ca(s) + 2H2O(g) Ca(OH)2(aq) + H2(g) |
| Reactions with air |
| The surface of calcium metal is covered with a thin layer of oxide that helps protect the metal from attack by air, but to
a lesser extent than the corresponding layer in magnesium. Once ignited, calcium burns in air to give a mixture of white calcium
oxide and calcium nitride.
|
| 2Ca(s) + O2(g)2CaO(s) |
| 3Ca(s) + N2(g)Ca3N2(s) |
| Reactions with halogens |
| Calcium is very reactive towards the halogens fluorine, chlorine, bromine and iodine, and burns to form calcium(II) dihalides.
|
| Ca(s) + F2(g)CaF2(s) |
| Ca(s) + Cl2(g)CaCl2(s) |
| Ca(s) + Br2(g)CaBr2(s) |
| Ca(s) + I2(g)CaI2(s) |
| The reactions with bromine and iodine require heat to enable the formation of the products.
|
| Reactions with acids |
| Calcium metal dissolves readily in dilute or concentrated hydrochloric acid to form solutions containing the aquated Ca(II)
ion together with hydrogen gas.
|
| Ca(s) + 2HCl(aq)Ca2+(aq) + 2Cl-(aq) + H2(g) |
Ca(s)