Do I have to cover my hair in saudia Arabia ?

So my mom is making me go to saudia Arabia :( and I was wondering 1- do I have to cover my hair ? 2- can I just wear a hijab ? 3- can I wear a sleeveless top ? 4- can I wear clothes that reveal the legs,arms and back ? 5- can I wear pants and a short sleeve shirt ? 6- what would happen if I didn't cover my hair or body and dressed in a over the shoulder top ? 7- what are the "dress rules" in saudia Arabia