[Shinta]

Hello, it seems as though I'm having major problems with chemical equations.  I have no problem decomposing or combining when the formula is given but I'm having a hard time extracting the formula when the question is in a word problem such as this:

The aluminum metal undergoes a combination reaction with oxygen in the air, what is the balanced equation?

I know aluminum is AL and oxygen is O but from there I'm lost.  I'm not asking for anybody to do the whole problem for me but a hint to get me going in the right direction would be appreciated.  Thanks.

[DrCMS]

What is the valence of Al and O?
How can you combine the two to satisfy both?