I need to write chemical formulas, how do I access the small keys at the bottom of the ? And the : keys?

You have to engage or turn on the number lock key. You do this by pressing down on that key, and make sure you see a light come on the keyboard,

Definitely you can, check your keyboard Numlock key then press once and light glow on the top, it means your Numlock key is ON and you can use all the right side keys. Please check it.