How many moles of ca atoms are in 534.0 g ca?

To answer this question, you need to understand the concept of molecular mass. Atom mass is made of the neutrons and protons and it will determine how much it masses. A Higher number of proton/neutron will result in a higher mass per mole of the atom. Calcium has 40g/mole mass. Then the amount of mole would be: 534g / (40g/mole) = 13.35 moles