The Atomic Theory

Ancient Greek philosopher

Matter is made of solid spheres he called "atomos".

cathode ray tube

discovered the electron

Plum Pudding Model (also called Blueberry Muffin Model or Chocolate Chip Cookie Model)

Gold foil experiment

discovered the positively charged nucleus

said the atom is mostly empty space except for the tiny, positive nucleus

Planetary Model (also called the Rutherford-Bohr Model)

used hydrogen to discover energy levels

said that electrons travel around the nucleus in SPECIFIC "orbits" that he called energy levels like the planets orbit the sun

Planetary Model (also called Rutherford-Bohr Model)

discovered the electron cloud

said electrons are most likely to be found at specific distances from the nucleus in what he called and electron "cloud"

energy levels are not two dimensional paths but are three dimensional shells

Electron Cloud Model