If the equation is not balanced, you have extra of one substance. If you try to do an experiment, you could wind up with a totally different outcome. Its kind of like baking a cake. If the ingredients aren't the right amounts, you dont get an edible cake.
Nitrogen monoxide has 1 oxygen atom and
Nitrogen dioxide has 2 oxygen atoms
The noble gases AKA the column with full outermost valence shells. (Group 18)
