- The atomic number is equal to the number of protons in an atom's nucleus.
- In a neutral atom, the number of electrons equals the number of protons, so the atomic number also gives the electron count.
- The atomic mass (rounded to the nearest whole number) is the sum of protons and neutrons.
- To find the number of neutrons, subtract the atomic number from the atomic mass: Neutrons = Atomic Mass - Atomic Number.
- For example, for copper (Cu): Atomic Number = 29 (so Protons = 29, Electrons = 29), Atomic Mass = 64, so Neutrons = 64 - 29 = 35.
- This method applies to all elements listed in the table.
Parent Tip: Review the logic above to help your child master the concept of atomic number and mass number worksheets.
