-
427 BCE
Plato
objects of matter must derive atoms from one of five different solid shapes -
400 BCE
Democritus
He believed all things were made out of atoms -
384 BCE
Aristotle
that everything wasn't made out of atoms, it was made of the 4 elements- earth, water, fire and air -
Robert Noyle
The volume of gas decreases with increasing pressure (Boyle's law) -
Lavoisier
The total mass of products is always the same (date is 1772-1794) -
The Alchemists
They developed some aspects of chemistry still used today- whether it be instruments or what melts different substances. -
John Dalton
atoms were the smallest particles of matter, atoms cannot be created nor destroyed, all atoms of the same element were identical. -
Dmitri Mendeleev
When the elements are all put in numerical order- it creates a pattern -
Robert Millikan
how to quantify an electron's charge -
J.J. Thomson
found electrons -
photoelectric effect
When light with a certain energy hits a metal- an electron may be locked loose -
Einstein
He mathematically proved atoms existed- and that liquids are made up of molecules -
Planck's Quantum Theory of Light
the energy of light is proportional to the frequency -
The Curies
Discovered polonium and radium -
Ernest Rutherford
Atoms are mostly empty space; all of an atom's matter comes from it's nucleus. -
Henry G. J. Moseley
the atomic number is number of positive charges in the nucleus of an atom -
Werner Heisenberg
He developed the electron cloud model -
Shrodinger Equation
H ^ ψ = E ψ \hat{H}\psi=E\psi H^ψ=EψH (a wave equation) -
Neils Bohr
He made a model of the atom -
James Chadwick
The existence of neutrons
