-
Antoine Lavoisier
Antoine Lavoisier made the first breakthrough in the study of chemical reactions. Lavoisier discovered that mass is conserved during a chemical reaction. Antoine Lavoisier discovery led to one of the main laws of chemical behavior, the Law of Conservation of Mass. -
law of conservation of mass
-
John Dalton
John Dalton was an English Chemist who adapted Democritus’s first suggestion of the existence of the atoms. He built on that theory and came up with his own improved one. Dalton’s Atomic Theory states that attempts to describe all the properties of atoms. -
daltons atomic theory
-
dmitri mendeleev
-
J.J. Thomson: Discovery of Electron
J.J. Thomson was famous for discovering the electron. He was experimenting with a Crookes, or a cathode ray, tube and demonstrating that cathode rays were negatively charged which led to the discovery of the electron. J.J Thomson also also realized that the atomic model at the time did not account for negatively or positively particles in the atom. J.J. Thomson connected his atomic model to a plum pudding. -
plu pudding
-
Robert Millikan
-
Gold Foil Experiment
Ernest Rutherford conducted this experiment to determine the structure of an atom. He realized that since atoms are neutral and electrons are negative there must be a particle with a positive charge to make the atomic neutrally charged. In the experiment, Rutherford found out that most of the space within the atoms is empty, there is a positively charged area in the atom which is now known as the nucleus, the central region of the atom is very small, but contains most of the atoms mass -
rutherford model
-
ernest rutherford
-
henery moseley
-
bohr planetary model
-
niels bohr
-
erwin schrodinger
-
quantum mechanical model
-
electron cloud model
-
james chadwick
-
Cathode Ray Tube: Discovery
The Cathode Ray Tube is a vacuum tube where a beam of electrons are focused into a small-cross section, in different positions and intensities on a display surface. The CRT creates images when its phosphorescent surface is hit by electron beams. While experimenting with the CRT J.J Thomson observed that positive charges attracted the cathode rays while negative charges refused the rays. Thomson concluded that the particles that make the cathode rays are negative because opposite charges attract.
