How many calcium atoms are in 31.2 g of calcium?

To find the number of atoms in calcium one has to multiply a given mole of Calcium by Avogadro's number since each mole of a substance contains 6.03 × 10²³.

Now, mol of Ca = mass of Ca ÷ molar mass of Ca
          mol of Ca = 31.2 g ÷ 40 g/mol
          mol of Ca = 0.78 mol

⇒ atoms of Ca = 0.78 mol × (6.02 × 10²³ atoms/mole)
                          = 4.696 × 10²³ atoms

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.