look at the atomic number using the periodic table. The Atomic number equals the amount of protons and the amount of protons equals the amount of electrons
1 moles -------- 6.02x10²³ atoms
?? moles ----- 7.4x10²¹ atoms
moles = 7.4x10²¹ / 6.02x10²³
= 0.01229 moles
hope this helps!
The answer to your question is D!
