If we have a sample of silicon (Si) atoms that has 14 protons, 14 electrons, and 18 neutrons

Question

What is the name of this specific silicon isotope?

silicon-14
silicon-32
silicon-46
silicon-153

Answer 1

The specific silicon isotope you are describing has 14 protons (which defines it as silicon) and 18 neutrons. To find the mass number of the isotope, you add the number of protons and neutrons together:

Mass number = Number of protons + Number of neutrons Mass number = 14 (protons) + 18 (neutrons) = 32

Therefore, this specific silicon isotope is called silicon-32.