-
427 BCE
Plato
Plato was a Greek philosopher who introduced the ideal geometric forms in atoms. Plato said that all atoms broke down mathematically into triangles. -
400 BCE
Democritus
Democritus belived all atoms were uniform, sold, hard and indestructible -
384 BCE
Aristotle
Aristotle was a Greek philosopher who did not think the atomic theory was accurate. He said everything was made of the four elements. -
Lavoisier
Antoine Lavoisier is best known for his discovery of oxygen and hydrogen. his first discovery happened in 1778 while his second took place in 1783 -
John Dalton
John Delton suggested that all matter is made of invisible atoms. He introduced the atomic theory. -
The Alchemists
The alchemists believed all metals were made of two components, mercury and sulfur. -
Newlands Law of Octaves
elements with similar qualities grouped together vertically on the periodic table. -
Robert Milkan
Robert Milkan discovered the charge of the electron by using an oil drop experiment. -
Mendeleev's PD. table
this is the periodic table that is still used today, it was invented in 1871 -
Photoelectric Effect
the photoelectric effect is a phenomenon where electrically charged particles are released from a material when it absorbs electromagnet radiation, this is described as an ejection of electrons. this effect was discovered by Rudolf Hertz in 1887. -
Discovery of Radioactivity
The discovery of radioactivity was found by a man named Henri Becquerel. Henri was inspired by the recent discovery of x-rays. he accidentally discovered radioactivity while experimenting on phosphorescent material. -
The discovery of the electron
the electron was discovered in 1897 by J.J. Thomson -
Planck's Quantum Theory Of Light
Light bulb filaments should be heated to a specific temperature of 3,200 kelvin. this is to ensure the most visible energy is emitted from the lightbulb as possible. -
Plum Pudding Model
The plum pudding model also known as the Thomason's plum model, defined as the chane in "plums" (positive and negitive charges) -
Rutherford's Gold Foil Experiment
Gold foil was shot with alpha particles, these particles are positivly charged most of these particles went right through the gold foil, thus determining that gold atoms are mostly empty space. -
Charge of the electrons
J.J. Thomson discovered the negatively charged electron, which caused problems for later scientists because electrons are usually neutrally charged -
Mosley's Atomic Number
Henry Mosely concluded that the atomic number is the number or positive and negitive charges in the atom. -
Bohr's Planetary Model
A model of the atom proposed by Neil Bohr that shows the positive and negative charge of atoms -
Schrodinger's Equation
A liner particle equation that shows the wave function of a quantum-mechanical system. -
Heisenberg's Uncertainty Principle
This principle state, we cannot know both the position and the speed of a particle, such as a photon or electron, with prefect accuracy. -
Discovery of the neutron
the neutron was discovered by Sir James Chadwick in 1932 -
The Discovery Of the Proton
the proton was discovered in early 1990s by Ernist Rutherford
