If a neon atom has a mass number of 20, how many neutrons are in the atom?
Neon has an atomic number of 10, which means it has 10 protons.
Mass number = number of protons + number of neutrons
If the mass number of neon is 20, and it has 10 protons, then the number of neutrons in the atom would be:
Neutrons = Mass number - Protons
Neutrons = 20 - 10
Neutrons = 10
Therefore, the neon atom with a mass number of 20 would have 10 neutrons.