No of moles of carbon atoms = 12 g/12g/mole = 1 mole We know that,Number of atoms = number of moles x Avogadro number = 1 x 6.022 x 1023 = 6.022 x 1023 In 1 atom of carbon there are 6 PROTONS and 6 neutrons = 12 NUCLEONS. The number of nucleons = 6.022 x 1023 x 12 = 7.2264 x 1024