# How to calculate the mass of a single atom?

If we know the molar mass of a certain element and Avogadro's constant, how can we calculate the mass of a single atom? Do we need to multiply the molar mass with Avogadro's constant?

$$\frac{\ce{12 g}~\ce{C}}{\pu{1 mol}~\ce{C}} \times \frac{\pu{1 mol}~\ce{C}}{\pu{6.022E23 atoms}} = \pu{1.993E-23 g//atom} = \pu{1.993E-27 kg//atom}.$$
That was the molar mass $$M$$ multiplied by $$1/N_\mathrm{A}$$, where $$N_\mathrm{A}$$ is Avagadro's constant.
Thus $$M/N_\mathrm{A}$$ gives you a calculation for mass of an atom for the specific element.
The average mass of a single element is its atomic mass on the periodic table (measured in $$\pu{u}$$, the unified atomic mass unit). One $$\pu{u}$$ equals about $$\pu{1.661E-27 kg}$$.