1. Find the moles of carbon:

* Molar mass of carbon: 12.01 g/mol

* Moles of carbon: (0.020 g) / (12.01 g/mol) = 0.00167 mol

2. Convert moles to atoms:

* Avogadro's number: 6.022 x 10^23 atoms/mol

* Atoms of carbon: (0.00167 mol) * (6.022 x 10^23 atoms/mol) = 1.00 x 10^21 atoms

Therefore, there are approximately 1.00 x 10^21 carbon atoms in 0.020 g of carbon.