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John Dalton
Conducted experiments with various chemicals and found that matter consists of smaller particles. He did not know their structure, but he knew it was something fundamental. -
Albert Einstein
Discovered that light absorption can release electrons from atoms. He called this the "Photoelectric Effect". -
Ernest Rutherford
Shown alpha particles through an atoms. MOst went through but occasionally some veered intensely off path. He inferred from these results that there must be electrons rotating around a positive center. -
Niels Bohr
Believed that electrons do not spiral into the nucleus and came up with rules for what they actually do.
Rule 1:'Electrons can orbit only at certain allowed distances from the nucleus.'
Rule 2: 'Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit.' -
Wolfgang Pauli
Believed that an electron should spin while it spins around the nucleus; it can spin in either direction. Said the spin consisted of a fourth quantum number: electron spin.
Pauli's Exclusion princible: " If an electron has a certain set of quantum numbers, then no other electron in that atom can have the same set of quantum numbers." -
Louise de Broglie
Predicted that since light exists as particles and waves that atom particles can behave as waves as well. -
Max Born
Believed the waves were waves of chance. The waves ripple in circles when an electron showed up. -
Erwin Schrödinger
Decided to take the idea that atom particles can act as waves further to making a model of it. It seemed to be like a vibration of an instrument string except it goes in a circle. He used the symbol 'psi' from the Greek lettering system for the symbol of his wave. -
Werner Heisenberg
Formulated the idea that no experiment can position and momentum simultaneously. People called this the 'Heisenberg uncertainty principle'. -
Paul Dirac
Wrote equations which predicted an unthinkable thing at the time- a positive electron. He did not even believe his theory at the time. -
James Chadwick
Discovered the neutron. Discovered it was a bit heavier than the proton. -
Carl Anderson
Conducted an experiment with cosmic rays which proved Dirac's equations and discovered the anti-electron. -
Hideki Yukawa
Used Heisenberg's uncertainty principle to suggest the another virtual particle exists in the fraction of a second. Later in 1947, a scientist named Cecil F. Powell discovered this perticle and called it the "pion". -
Max Planck
A proffesseur in Berlin. He showed that when you get atoms to vibrate enough then you can measure their energy. An efficient way of doing this was to heat the atom. He called their energy quanta. -
J.J. Thomson
Discovered the electoron and created a model of the possible structure of an atom. He knew electrons have a negative charge and decided that matter must have a positive charge.
