Physics·Nuclear Physics · NSSCO 6.1
The nucleus & isotopes
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Journey right into the heart of matter. Meet the nuclear model of the atom — a tiny, dense nucleus of protons and neutrons with electrons orbiting in shells — and see how Rutherford's famous gold-foil experiment revealed it. Learn the proton number Z and the nucleon number A, read the nuclide symbol like a scientist, work out the protons, neutrons and electrons in any atom, and understand isotopes and the many ways we use them.
What you'll learn in this lesson
By the end you should be able to (NSSCO Physics 6.1):
- Describe the nuclear model of the atom: a tiny dense nucleus of protons and neutrons, with electrons orbiting in shells
- Outline Rutherford's (Geiger–Marsden) gold-foil scattering experiment as evidence for the nucleus
- Use the term proton number (atomic number), Z, and nucleon number (mass number), A
- Use the term nuclide and the nuclide notation ᴬ Z X
- Work out the numbers of protons, neutrons and electrons in an atom from Z and A
- Define isotopes as atoms with the same proton number but different nucleon number
- Give and explain practical applications of isotopes (carbon dating, medicine, industry, power)
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