-
Law of conservation of mass
The law of conservation of mass is a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system. It was discovered by Antoine Lavoisier. -
law of definite proportions
Joseph Louis Proust created this law which states that every pure substance always contains the same elements combined in the same proportions by weight. -
Atomic theory
John Dalton came up with the atomic theory that states that all matter is composed of small indivisible particles called atoms. -
Spherical model of the atom
John Dalton Created the spherical model. -
Law of Definate Proportions
Law stating that every pure substance always contains the same elements combined in the same proportions by weight. It was discovered by John Dalton. -
Cathode Ray Tube Experiment
J.J. Thompson put a pair of metal cylinders with a slit in them and connected them to an electrometer.He found that when the rays entered the slit in the cylinders, the electrometer measured a large amount of negative charge. from this, he created the plum pudding model and discovered the electron. -
Plum Pudding Model
J. J. Thompson created the plum pudding model. you can imagine the pudding itself is positively charged and the plums are the negatively charged electrons. -
Discovery of the electron
J.J. Thompson discovered the electron from the Cathode Ray Tube Experiment. -
Nuclear model
Ernest Rutherford created the nuclear model and described the nucleus as a tiny, dense, positively charged core. He described negative constituents, called electrons, as rotating around the nucleus like planets around the sun. He discovered this by doing his gold foil experiment in which he would shoot alpha particles through a thin sheet of gold foil and very rarely he would see some bounce back so he realized the atom was mostly empty space but had electrons floating around it. -
Discovery of the nucleus
Ernest Rutherford fired energetic particles at a foil, and measured the deflection of the particles as they came out the other side. He did this to test the plum pudding model.He found that most of the energetic particles were not deflected at all. The ones that were deflected went directly back and he found that atoms had extremely small, dense lumps of matter inside. From this he discovered the nucleus and created the nuclear model. -
The Bohr Model
The Bohr model has 4 principles. Electrons assume only certain orbits called stationary orbits around the nucleus. Each orbit has an energy associated with it. Light is emitted when an electron jumps from a higher orbit to a lower orbit and taken in when it jumps from a lower orbit to a higher orbit. The energy and frequency of light emitted or taken in is given by the difference between the two orbit energies. -
Electron cloud model
Erwin Schrodinger created the electron cloud model. -
Discovery of the Proton
Ernest Rutherford discovered that nitrogen under alpha-particles ejected hydrogen nuclei. He concluded the hydrogen nucleus as an elementary particle and named them protons. -
Quantum theory
A theory of matter and energy based on the concept of quanta. Once Louis de Broglie had his matter-wave hypothesis the true importance of quantum mechanics became much more clear. With help from Paul Dirac, Werner Heisenberg, Wolfgang Pauli, and Erwin Schrödinger the quantum theory became easier to understand. -
Uncertainty Principle
Werner Heisenberg used a double slit experiment to find that as he made the slit more narrow, the laser on the wall would get more narrow as well until he reached a certain point when the laser on the wall would get larger. The uncertainty principle states that you cannot simultaneously know the position and momentum of an object. -
Neutrons
James Chadwick discovered neutrons. He used scattering data to calculate the mass of this neutral particle.
