An atom has 14 protons and 15 neutrons, what is its mass number? i'm desperate 20 pts.

The amount of protons is the same as the atomic number. You look for 14, silicon, and look at the mass, 28.086

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.