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Chemistry - Unit 1

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schoolstudycanada's version from 2018-02-15 04:21

Section

Question Answer
Democritus300 B.C
- Matter can be broken into smaller and smaller pieces
- Atoms are smallest particle and indivisible
John Dalton's Atomic Model1808
- His theory agreed with previous theories of atoms.
- atoms can't be destroyed or subdivided
- atoms of same element have same properties
- atoms combine in special ratios (proportions) when forming compounds
J.T Thompson"Chocolate cookie model" (1904)
- positively charged pudding in which negative electrons are embeded
Rutherford's Gold foil experimentRt shot particles through a gold foil and expected them to go straight through; except some of them didn't; which indicated towards magnetic interference in concentrated areas (a center [nucleus]).
- The experiment also deduced the nucleus was positive as it deflected negative electrons and the atom was empty as most particles went through.
Rutherford nuclear model1911
- Nucleus with electrons surrounding it.
- This model was wrong due to the line spectrum, where the light would appear to have coloured lines
Niels Bohr model(1914) closest to modern diagram of atom
Electron Cloud modelregion where very likely to find electron but still unsure of position (heisenburg principle)
Standard Atomic NotationMass (protons + neutrons)
<space>Atomic symbol
atomic number (amount of protons)
IsotopeAtoms of same number of protons but different amount of neutrons
Do all elements have isotopesMost of them do.
Heavy waterDeuterium. Used to absorb energy
Three main Hydrogen isotopeswaserstoff, deuterium, tritium. # of neutrons changes: 0, 1, 2
RadioisotopeIsotope with unstable nucleus. (tritium)
- used in cancer treatment & dating fossils (the last one uses half-life decay)
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