## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

We can find the mass of one atom as: $m_a = \frac{\rho}{\rho_N}$ $m_a = \frac{1750~kg/m^3}{4.39\times 10^{28}~atoms/m^3}$ $m_a = 3.986\times 10^{-26}~kg$ We can find the total number of protons or neutrons in the atom as: $A = \frac{m_a}{1.67\times 10^{-27}~kg}$ $A = \frac{3.986\times 10^{-26}~kg}{1.67\times 10^{-27}~kg}$ $A = 24~amu$ The element's atomic mass number is 24 amu.