Scientists who discovered the atom

Murray Gell-Mann

American scientist in 1963. discovered quarks- particles that make up three main subatomic particle's (protons neutrons and electrons) he discovered the up-and-down quarks have charges. Up + 2/3, down -1/3

John Dalton

British chemist 1808 who discovered that atoms are thought to be solid marble like objects Daltons Theory 1) all substances made of atoms which are the smallest particle of matter 2) all atoms of the same element are the same. All atoms of different elements are different. 3) atoms can join in a specific ratio to form compounds

J.J. Thomson

British physicist in 1897 who did the vacuum tube experiment that discovered electrons and the plum pudding model which discovered that electrons have a negative particles and that electrons are suspended in a jelly like substance with a positive charge

Ernest Rutherford

British physicist in 1911. studied under JJ Thompson. gold foil experiment that discovered positive nucleus and large spaces. also discovered electrons orbiting around the nucleus that holds protons

James Chadwick

British physicist in 1932. student of Rutherford. discovered neutrons and said they were in the nucleus

Niels Bohr

Danish scientist in 1913. Worked with Rutherford and discovered positive central nucleus with orbiting electrons in distinct orbitals or shells

Democritus

Philosopher 450 BC who discovered that the smallest piece of matter is the atom.