* Combustion is a chemical process involving the rapid reaction between a substance with an oxidant, usually oxygen, to produce heat and light.

* In the case of magnesium reacting with oxygen, the magnesium acts as the fuel and oxygen acts as the oxidant.

* The reaction produces magnesium oxide (MgO), which is a white powdery solid.

Here's the balanced chemical equation for the reaction:

2 Mg + O₂ → 2 MgO

Key characteristics of combustion reactions:

* Exothermic: They release heat energy.

* Rapid: They occur quickly.

* Produce light: They often emit light, like the bright white light produced by burning magnesium.

* Involve oxygen: Oxygen is typically required as the oxidant.