Magnesium [Mg] + Oxygen [O2] --> Magnesium oxide [MgO]
See, When magnesium is burned in air,it reacts with oxygen, here both of them(Mg & O) gets combined with each other, thus it is a combination reaction.
Now, balance this equation first;
Now, as you can see that 2 molecule of magnesium gets combined with one molecule of oxgyen and forms 2 molecules of magnesium oxide. And let us understand how they are bonded with each other;
- Electrons in Mg: 2,8,2
- Electrons in O: 2,6
Mg × × • • • •
• O • • O •
• • • •
Mg × ×
- See,Mg has 2 electrons in its outermost shell while oxgyen has 6 electron in its outermost shell & both of them wants to get stable so, Mg will give its 2 electrons to oxgyen and it will have 8 electrons with it and a charge of +2 on the other hand oxygen will gain these 2 electrons amd it will also get its octet complete with a charge of -2
and as 2 Mg are bonded with 2 oxygen, they will together result in 2 molecules of magnesium oxide.