Chemistry Scientists

Democritus

First proposed the idea of the smallest piece of matter; coined the term “atomos” = indivisible.

Dalton

Stated that all matter is made of atoms; atoms are small, indivisible particles; all atoms of an element are the same; atoms of different elements are different.

Thomson

Discovered the electron with with rode ray tubes; developed the plum pudding model of the atom.

Rutherford

Discovered the nucleus with his gold foil experiment; determined that atoms have a small, dense, positively charged nucleus and that most of the atom is empty space where elements orbit.

Bohr

Developed quantum theory of atomic structure; electrons are in energy levels around the nucleus; a question of energy is required to move an electron to a higher energy level.

Moseley

Developed “periodic law” which states that elements are arranged in the periodic table not by increasing mass, but by increasing numbers of protons.

Schrodinger

Developed orbital theory; energy levels are not circular orbits, but rather clouds of varying shapes and sizes in which the probability of finding on electron is high.

Chadwick

Discovered the neutron.