Answer:
Carbon- 6 neutrons
calcium- 20 neutrons
Step-by-step explanation:
the nucleon mass ( sum of no. of protons and neutrons) of Carbon is 12 and it's atomic number (no. of protons) is 6. 12-6=6
same for Calcium, but calcium has a nucleon mass of 40 and an atomic number of 20. 40-20=20