Chapters+1+and+2+history+of+chemistry+and+discovery+of+atoms

Main ideas Hunters and gatherers - heat treated wood of their spears - noticed hardening Cooks - made compounds - first chemists metalurgists - in stone age Wizards - collected herbs and poisons Alchemists - wanted to urn lead into gold

All of these were the precursors to modern scientists and chemists in particular they observed, hypothesised, and tested the hypotheses and from there came up with theoris about how the world worked. Famous chemists Priestly discovered oxygen Lavoisier - the law of conservation of mass Dalton - that atoms existed as hard indivisible balls and each was different to others and hence elements were identified Tried to weigh them to determine differences. Mendeleev - arranged known elements in order of weight. - the first periodic table

Upto now no idea of protons neutrons and electrons The history of the structure of the atom is as follows 1804- Dalton - hard balls 1897 Thomson - plumb pudding model - some positives in there with some negatives 1911Rutherford nucleus of positives and electrons orbiting 1913 Bohr - distinct shells for electrons and energy levels - Flame tests 1926 Schrodinger - approximate position of electrons - uncertainty principle 1932 Chadwick - neutrons