Who was Dalton?
John Dalton was an english chemist and physiest. He is best known for his advocacy of the atomic theory and his research into colour blindness .
What did he think?
He thought that all matter consisted of tiny particels called atoms.atoms could
not be divided into smaller particels. Atoms of the same kind are called elements.
Atoms combine in whole number ratios.
Why did he think this?
He thought this because the electrons go around the nucleus in orbitals or energy levels.
Who was Thompson?
J.J Thompson was was a British scientist. Thomson is credited for the discovery of the electron, of isotopes, and the invention of the mass spectrometer.
What did he think?
He called his theroy 'plum pudding' to explain the structure of the atom.
An atom is a positively shpere with negatively charged electrons embedded in it.
Dalton dicovered the electron, the raisn in the pudding.
Why did he think this?
Only electrons with specific amounts of energy could exist at each level.
Who was Rutherford?
Ernest Rutherford was a nuclear physicist who became known as the "father" of nuclear physics. He pioneered the orbital theory of the atom through his discovery of Rutherford scattering off the nucleus with his gold foil experiment.
What did he think?
Rutherford found the nucleus of the atom. He did an experiment with alpha particles wich he fired at a gold foil sheet, he expected them to go through but some did not.
Rutherford then concluded that all the positive chrage is concentrated in the centre of the atom - the nucleus. One problem with Rutherfords ideas is that he thought the
electrons lost enregy and spiralled towards the centre of an atom causing it to collapse.
Why did he think this?
He thought his model proposed that electrons could move from one level to another
by gaining or losing 'packets' of energy.
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