Why should Mg combine with O2?

Question

Magnesium burns brightly in oxygen to give magnesium oxide, which contains the ions mg2+ and 02- . The formation of both these ions from their elements is strongly endothermic. Why, therefore, should magnesium combine with oxygen?

Answer 1

The reaction between Mg and O2 is highly exothermic. So, which reaction is endothermic? Mg is surplus in electrons and Oxygen is deficit in electrons. So, a reaction is natural, though it may not take place at room temperature spontaneously unlike Sodium or Potassium and oxygen.

Answer 2

Both the above answerers have not got the point.
Most of the individual processes for forming Mg2+ and O2- ions are indeed endothermic. But what drives the reaction is the massive lattice enthalpy of formation - the energy given out when these two oppositely-charged gaseous ions come together and form a solid ionic lattice. It completely outweighs all the endothermic factors, and makes for a large, negative enthalpy of formation.

Answer 3

you said it: it burns. burning is an exothermic process.