Balance the following chemical equation:
(?) Al +(?) O2 >(?)Al2O3

if the concentration of products is decreased, the equilibrium will shift toward the products). add an inert gas (one that is not involved in the reaction) to the constant-volume reaction mixture: this will increase the total pressure of the system, but will have no effect on the equilibrium condition.

explanation:

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

you need to have a picture of the atom that way we can answer it