Question

How many moles are 1.20 x 10^25 atoms of phosphorous

Answer 1

How many moles are $1.20 \times 10^{25}$ atoms of phosphorous

$$\begin{array}{l} \nu = \frac{N}{N_{A}} \\ \nu = \frac{1.2 \times 10^{25}}{6.02 \times 10^{23}} = 0.2 \times 10^{2} = 20 \text{ mol} \end{array}$$

20 mol