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Democritius
Democritius believed that matter was made up of invisilble particless called atoms. -
Antonie Lavosiser
Antonie Lavoisier process of combustion named elements and of oygen and hydrogen H2+O2=2H2O -
Law of Conservation of Mass
States that mass is neither created nor destroyed in any chemical reaction.The mass of substances produced by a chemical reaction is always equal to the mass of the reacting substances. -
Dalton's Atomic Theory
All matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and propertiesCompounds are formed by a combination of two or more different kinds of atoms. -
Dmitri Mendeleev
Constructed the perodic table and predicted the properties of undiscovered elements. -
Cathode Ray Tube
A vacuum tube in which a hot cathode emits electrons that are accelerated as a beam through a relatively high voltage anode, further focused or deflected electrostatically or electromagnetically, and allowed to fall on a phosphorescent screen. -
JJ Thomson
Dscovered the electron and determined the mass of charge ratio of the particles. -
Plum Pudding Atomic Modell
In 1897 J.J. Thomson discovered the electron, a negatively charged particle more than two thousand times lighter than a hydrogen atom. -
Robert Millikan
In 1909 Robert Millikan was the first to find the charge of an electron in his now-famous oil drop experiment. In the experiment, tiny oil drops are sprayed into a uniform electric field between a horizontal pair of oppositely charged plates. -
Rutherford Model
Dicovery of the nucleus and proposed nuclear model. Rutherfords experiment is called Rutherford's Gold Fall- bombarded a thin gold fall with alphs articels(positive charge) Rutherford concluded that atom was mostly space. -
Henry Moseley
A British chemist, Henry Moseley studied under Rutherford and brilliantly developed the application of X-ray spectra to study atomic structure; Moseley's discoveries resulted in a more accurate positioning of elements in the Periodic Table by closer determination of atomic numbers. -
Bohr Planetary
The Bohr Model is probably familar as the "planetary model" of the atom illustrated in the adjacent figure that is used as a symbol for atomic energy In the Bohr Model the neutrons and protons occupy a dense central region called the nucleus, and the electrons orbit the nucleus. -
Gold Foil Experiment
Rutherford concluded the atom was mostly empty space with a positive charge awas concenrated in a tiny volume whcih he called the nucleus. -
Quantum Mechanical Model
The quantum mechanical model is based on mathematics. It is more difficult to understand than the Bohr model, it can be used to explain observations made on complex atoms. -
Erwin Schrodibger
A powerful model of the atom was developed by Erwin Schrdinger. Schrdinger combined the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom. -
Ernst Rutherford
Atom-splitting experiments -
Niels Bohr
Niels Bohr applies quantum theory to Rutherford's atomic structure by assuming that electrons travel in stationary orbits defined by their angular momentum. This led to the conclusion of possible energy levels for these orbits. -
James Chadwick
Discovered the neuron no charge and found in the nucleus -
Electron Cloud Model
the electron cloud is a way to describe where electrons are when they go around the nucleus of an atom. The electron cloud model is different.
