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Democritus
was a ancient philosopher living between the ages of 460 BC and 370 BC. Democritus claimed that everything is made up of atoms and that atoms have empty space between them. That they are indestructible and always in motion. Atoms come in all types of shapes and sizes. -
Antoine Lavoisier
Antoine named both the oxygen and hydrogene element in 1778 and 1783. -
John Dalton
Dalton discovered that matter is made up of atoms which are indivisible and indestructible and that all atoms of a given element are identical in properties and mass. Atoms cannot be created or destroyed. Also, a combination of two or more different kinds of atoms is called a compound -
Dmitri Mendeleev
Back in the late 1860s, Mandeleeve organized the known elements and started looking for patterns in properties. He decided to place the elements in order of increasing atomic mass. Through this the Periodic Table was created. -
J. J. Thomson
In 1897, Thomson discovered the electron. He also discovered that an atom consists of a sphere of positive charge with negatively charged electrons on it and that an atom is electrically neutral. -
Robert Millikan
Millikan was able to discover the mass and charge of the elctron through measuring the charge on an electron with an oil-drop expieriment. -
Ernest Rutherford
Back in 1909, Rutherford conducted an experiment and ended up discovering that some of the alpha particles ended up bouncing back instead of most of them actually going through the gold foil. -
Niels Bohr
Bohr redefined Rutherford’s model in 1931, he proposed that electrons orbit the nucleus without losing energy and could only move in fixed orbits of specific energies. -
Erwin Schrodinger
Erwin used mathematical equations to finding an electron in a certain position back in 1926. -
Henry Moseley
Moselev had developed the application of X-ray spectra to study atomic structure. He then also discovered accurate positioning of the elements in the Periodic Table. -
James Chadwick
In 1932, Chadwick proved the existence of neutrons. He stated that the atomic number is determined by the numbers of protons that are in an atom. -
Quantum Mechanical Model
The Quantum theory states and confirms that matter has properties that are associated with waves, and so the model uses mathematics and is based on this theory. -
Bohr Planetary Model
The Planetary Model is used as a symbol for atomic energy. The neutrons and protons use a dense and central area which is the nucleus and the electrons orbit the nucleus -
Electron Cloud
The Electron Clous was created and developed by both Erwin Schrodinger and Werner Heisenberg. The Electron Cloud displays where the electrons are located when they rotate around the nucleus of an atom. This model also clearly states that electrons do not orbit the nucleus. -
Cathode Ray Tube
The Ray Tuve was invented by Ferdinand Braun back in 1897 but was created/made famous by J.J. Thomson. In the Cathode Ray Tube the electrons are accelerated into a tube, onto a screen that dispays pictures and images.
