- The atomic number represents the number of protons in an atom's nucleus, which defines the element. The mass number represents the total number of protons and neutrons in the atom's nucleus.
- Isotopes are atoms of the same element (same atomic number) that have different numbers of neutrons (and therefore different mass numbers). They are similar because they have the same number of protons and electrons (in a neutral atom), giving them identical chemical properties. They are different because they have different numbers of neutrons, leading to different atomic masses and potentially different nuclear stability.
- The atomic mass of an element represents the weighted average mass of all its naturally occurring isotopes, based on their relative abundances.
- O: Atomic number 8, Mass number 16, Protons 8, Neutrons 8, Electrons 8
- Al: Atomic number 13, Mass number 27, Protons 13, Neutrons 14, Electrons 13
- P: Atomic number 15, Mass number 31, Protons 15, Neutrons 16, Electrons 15
- K: Atomic number 19, Mass number 39, Protons 19, Neutrons 20, Electrons 19
- Br: Atomic number 35, Mass number 80, Protons 35, Neutrons 45, Electrons 35
- Zn: Atomic number 30, Mass number 65, Protons 30, Neutrons 35, Electrons 30
- Pb: Atomic number 82, Mass number 207, Protons 82, Neutrons 125, Electrons 82
- Te: Atomic number 52, Mass number 128, Protons 52, Neutrons 76, Electrons 52
- Ru: Atomic number 44, Mass number 102, Protons 44, Neutrons 58, Electrons 44
- Hg: Atomic number 80, Mass number 198, Protons 80, Neutrons 118, Electrons 80
- Cs: Atomic number 55, Mass number 133, Protons 55, Neutrons 78, Electrons 55
Parent Tip: Review the logic above to help your child master the concept of atom structure worksheet.
