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First Element Discovered
Development of The Periodic TableHennig Brand discovers Phosphorus through scientific inquiry. -
Dalton's Atomic Theory
Dalton Atomic TheoryAll matter is composed of atoms
Stated the following:
Atoms cannot be made or destroyed
All atoms of the same element are identical
Different elements have different types of atoms
Chemical reactions occur when atoms are rearranged
Compounds are formed from atoms of the constituent elements -
Döbereiner's Law of Triads
Döbereiner's Periodic TableEach of Dobereiner's triads was a group of three elements. The appearance and reactions of the elements in a triad were similar to each other. -
Use of Atomic Weights
[Precursors to the Periodic Table](http:http://www.bpc.edu/mathscience/chemistry/history_of_the_periodic_table.html//)A.E.Beguyer de Chancourtois was the first person to make use of atomic weights to reveal that the elements were arranged according to their atomic weights. -
Law of Octaves
Precursors to the Periodic TableJohn Newlands, an English chemist, proposed the Law of Octaves which stated that elements repeated their chemical properties every eighth element. -
More Element Discoveries
Development of The Periodic Table63 elements have been discovered. -
Thomson Model of The Atom
Atomic ModelJoseph John ThomsonThomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. -
Rutherford Atomic Model
ModelRutherford ModelStates the atom as having negative orbiting electrons. Also, most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space -
Bohr Atomic Theory
Bohr Atomic StructureBohr Model
Bohr suggested the revolutionary idea that electrons "jump" between energy levels (orbits) in a quantum fashion.
