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Chemical properties of Alkaline earth metals: How alkaline earth metals burn in air

Answer Text:
Chemical properties of Alkaline earth metals.
1. Burning alkaline earth metals in air.
- Alkaline earth metals react burn in air to form corresponding oxides.
- More reactive alkaline earth metals may also react with atmospheric nitrogen to form corresponding nitrides.
Examples:
Magnesium.
- Burns in air with a blinding brilliant flame forming a white solid.
- The white solid is a mixture of magnesium oxide and magnesium nitride.
Equations:
Reacting with oxygen: `2Mg(s) + O_2(g) → 2MgO(s)`
Reacting with nitrogen: `3Mg(s) + N_2(g) → Mg_3N_2(s)`
Calcium.
- Burns in air with a faint orange flame forming a white solid.
- The white solid is a mixture of calcium oxide ad calcium nitride.
Equations:
Reacting with oxygen: `2Ca(s) + O_2(g) → 2CaO(s)`
Reacting with nitrogen:`3Ca(s) + N_2(g) → Ca_3N_2(s)`
Note:
- The trend in the reactivity of alkaline earth metals when burning in air is not clear; due to the oxide coating on the calcium that tends to slow down the reaction of calcium in air.
- For this reason it is important to polish the surfaces of alkaline earth metals before using them in experiments.