Step-by-step explanation:
You can simply subtract the atomic number from the mass number in order to find the number of neutrons. If the atom is neutral, the number of electrons will be equal to the number of protons.
Remember!
1. Your mass number is the total number of neutrons and protons within the atom.
2. Your atomic number is the amount of protons within the atom.
3. For neutral atoms, the electron number is the same as the atomic number.