Atomic Structure

Atomic Structure

1. Isotopes are atoms that have the same number of protons, but a different number of nuetrons

2. Atoms contain 3 sub-atomic particles, neutrons, electrons, and protons. The protons and neutrons are found in the nucleus, and the electrons are in the outer energy layers of the atom

3. If one atom loses an electron then it becomes positive ion, if an atom gains an electron it becomes a negative ion.

4. Plum Pudding Model

   • The plum pudding model was a scientific idea about the atom being like a plum pudding. They thought the atom was a sphere and the electrons were in the middle of the sphere dotted around randomly like the plums in a plum pudding model.
   • An experiment was carried out in 1905 that proved the plum pudding model could not be right

5. Rutherford Scattering

   • A scientist called Ernest Rutherford designed an experiment to test the plum pudding model
   • A beam of alpha particles are sent through a thin strip of gold foil. The scientists expected the alpha particles to pass straight through, but something else happened
   • Some of the alpha particles emerged from the foil at different angles, and some even shot straight back.
   • The scientists realised that the positive alpha particles were being deflected from the tiny concentration of positive charge in the atom
   • As a result of this experiment the plum pudding model was replaced with the by the nuclear model of the atom