How is the atomic mass of an element calculated

One of the few xenon compounds that form is cesium xenon heptafluoride (csxef7). how many moles of csxef7 can be produced from the reaction of 13.0 mol cesium fluoride with 12.5 mol xenon hexafluoride? csf(s) + xef6(s) csxef7(s)

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? a) 6 b) 8 c) + 1 d) 12 e) 18

Drug abuse will not lead to physical and psychological dependence. true or false ?