Question

Which equation is balanced?

2Al+3O2→Al2O3

2Na+F2→2NaF

Mg+O2→2MgO

2Al+F2→2AlF3

Answer 1

the 1st one is balanced, the 2nd isn't (the number of Mg differs from left 1 to right 2).

The third is also not balanced, 2 F left,2*3=6 on the right