g An atom of carbon has six protons, six electrons, and six neutrons. What is the atomic mass of the carbon atom

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

What is the formula that this ionic compounds could form sr2+p3-o2-

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg