The Discovery of the Atom

Empedocle's Idea

450 BCE

Empedocles had an idea that atoms were made out of either 4 elements which were earth, air, fire and water.

Democritus Discovers the Atom

400 BCE

Democritus had a believe that atoms were made of tiny little particles, and what were inside of these particles affected the type of matter these particles were.

John Dalton Proposal

1808

John Dalton had a proposal that stated, that every single atom in one single element is the same atom.

J.J Thomson

Apr 30, 1897

J.J Thomson conducted expirements in his lab which proved that atoms do indeed have a negative charge.

Ernest Rutherford Discovery of an Atom's Mass

1910

Ernest Rutherford found that an atom is mainly just an empty space but inside of the nucleus of the atom is where it holds the most of it's mass.

Niels Bohr Proposal of Hydrogen Atom

1913

Niels Bohr made the Bohr atom model and in this model of the atom, in which he proposed that electrons orbited around the atom nucleus

Louis DeBroglie Idea of Electrons

1924

Louis DeBroglie was the first person to suggest the idea that these particles that we call atoms today have electrons inside of them, and he also suggested to not only describe this as a particle but as waves.

Erwin Schrödinger Wave of Equation

1926

Erwin Schrödinger was the first person the calculate the first wave equation of energy levels inside of electrons.

Werner Heinsberg Quantum Mechanics

1927

Werner Heinsberg discovered that a particles momentum or state cannot be known precisley and he found this out using Quantum Mechanics

James Chadwick Neutron

1932

James Chadwick is mostly known for his discovery of the neutron which he stated that it is a particle that does not have an electric charge in it.