Download History of Atomic Structure Notes

WARM UP
1.List 7 things you already
know about atoms.
2.List anything you know
about the scientists who
“discovered” atoms.
History and Structure of
Atoms
~400 B.C. – Democritus
• “a tom” (no cut)
particles
1808 – John Dalton
• Atomic Theory
– Matter is made of atoms.
– All atoms of an element
are identical.
– Compounds combined
atoms
– You can’t destroy atoms.
1900’s – J.J. Thomson
• Discovers electron
–Cathode ray tube
1900’s – R.A. Millikan
• Electron’s charge and mass
– Oil drop experiment
1900’s – Marie Curie / Henri Becquerel
• Discover protons
– Radiation
The Big Bang Theory
Plum Pudding Model
• Electrons and +
particles evenly
spread
• J.J. Thomson
1910 – Ernest Rutherford
• Discovers solid nucleus made of protons
– Gold foil experiment
Rutherford Model
• Small proton nucleus, electrons in lots of
“empty” space
1913 – Max Planck
• Electrons have quanta (“steps” of energy)
– Emission spectra
Planetary (Bohr) Model
• Small nucleus
with electrons in
orbitals
• Niels Bohr
Electron Cloud Model
• Werner Heisenberg
– Electrons move
randomly
Electron Cloud Model
The Big Bang Theory
1932 – James Chadwick
• Discovers neutron
– Beryllium foil emission experiment
The Modern-Day Atom
WRAP UP
1.Name 5 scientists who
studied atoms.
2.Describe the contributions
of the 5 scientists you
listed.