-
He discovered the law of proportions, The law of proportions states that atoms of each element are the same size, mass and shape, but are different from atoms of other elements. He came up with the model named "The billiard ball model'. -
JJ Thomson discovered the first electron. He was experimenting with cathode ray tubes that showed all atoms that exist have tiny subatomic particles that are negatively charged called electrons. He made the "plum pudding" model" to show that they are scattered out in an atom inside a positively charged soup. -
He discovered that atoms are mostly empty space. He also found that they are positively charged and that the nucleus is very dense, small and carries most of the atom's mass using the gold foil experiment. -
He created the initial model of the atom. He found that electrons orbit around the nucleus in prescribed patterns. It is sent out as radiation if electrons jump to a lower-energy orbit. His model also shows why atoms only emit light off of wavelengths that are fixed. -
He proved that existence of neutrons and that elementary particles devoid of any electrical charge.