1. ATOMIC HISTORY & ISOTOPES

6. Thomson’s experiment involved
a cathode ray tube with a gas at low
pressure. The gas flowed from the
negative end to the positive end of the
tube. Because the gas consisted of electrons, it
was repelled by the negative end of the magnet and attracted by the positive end of the magnet showing that an electron is negatively charged

7. THOMSON’S MODEL IS CALLED THE PLUM PUDDING MODEL
Thomson explained that the model was like plums representing the electrons in pudding represented as protons

9. Rutherford’s Gold Foil experiment involved shooting positively charged alpha particles through a thin piece of gold foil. He expected the alpha particles to pass straight through or get struck in the positive part. Instead most alpha particles passed straight through but a few were deflected or bounced straight back. This lead to the conclusion that an atom is mostly empty space but has a very small positively charged center (nucleus)

12. ISOTOPES
ISOTOPES: Describe an isotope, compare the properties of the isotope of an element and deduce the symbol of an isotope given its mass number and atomic number.
RELATIVE MASS (AVERAGE ATOMIC MASS): Calculate the non integer relative mass and abundance of isotopes from given data.