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Atomic Theory Scientists and their contributions
Terms in this set (12)
first proposed the idea that all matter was made up of tiny indivisible particles called atomos
determined the Law of Conservation of Matter by extensive experimentation
determined the law of constant composition (compounds always contain the same proportion, by mass, of elements)
formulated an atomic theory of matter with 4 postulates:
1. Elements are composted of small particles called atoms.
2. All atoms of a given element are identical. *
3. Atoms are neither created nor destroyed in chemical reactions.
4. Compounds always contain the same proportion of elements.
performed a CRT experiment and determined that the ray was composed of negative particles, call these electrons, determined the mass-charge ratio for an electron, came up with the "plum pudding" model of the atom
performed an "oil-drop" experiment, determined the charge of one electron and using the known mass-charge ratio, was able to calculate the mass on one electron (9.11x10^-28g)
The Curies (Marie and Peirre)
discovered two other radioactive elements, polonium and radium
performed the gold foil experiment, determined that atoms contained a very small, positively charged core at the center, called this core the nucleus, came up with the nuclear model of the atom (with electrons orbiting around the nucleus)
found that all atoms of a given element contained the same number of protons in the nucleus
developed the quantized orbit model of the atom, electrons can only reside in certain energy levels
expanded the idea that electrons behaved as particles AND waves, this developed the quantum mechanical model of the atom
discovered the neutron