Scientists. The atom. Democritus . - 400 BC- Greek philosopher - No experimenting Matter made up of indivisible particles = “ atomos ”. Dalton. 1801: Thomas Jefferson President 1802: John Dalton experimented and concluded…. 1806: Fall of Roman Empire . Dalton.
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- 400 BC- Greek philosopher
- No experimenting
1801: Thomas Jefferson President
1802: John Dalton experimented and concluded….
1806: Fall of Roman Empire
1. Matter made up small particles= atoms
2. Atoms of same element are identical
3. Chem. Rxn atoms separate, join, or rearrange
4. Atoms of different elements can combine in whole number ratios: compounds.
- Uranium was found to emit strange energy:
- Radioactivity: warm to the touch
- Can unlock secrets to the atom
Concluded Uranium atom gave off radiation
( but another chemist discovered first)
Found Radium – led to cancer fighting drugs
Won two Nobel Peace Prizes
Kept radioactive materials in her pocket
Died of leukemia from radioactive materials
(could be broken into parts)
majority passed straight through
some bounced @ large angles & straight back
chance of finding
Thompson 1904- “plum pudding”
Quantum mechanical model
Can not know the speed and the location of the e- at the same time