2. The electron was discovered by scientist, J.J Thompson by experimenting with Crookes, or cathode ray, tube.
3. The main difference between Rutherford and Bohr model is that Rutherford model does not explain the energy levels in an atom whereas Bohr model explains the energy levels in an atom.
4.
- Oxygen-16 has eight protons, eight neutrons, and eight electrons.
- Oxygen-17 has 8 protons, 8 electrons, and 9 neutrons.
- Oxygen-18 has 8 protons, 8 electrons, and 10 neutrons.
Hope this helps. Good luck on your learning journey :)