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Period: 460 BCE to
History of the atom
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460
democritus
born in Abdera, Greece
He was a Philosopher best known for saying that everything is made of atoms and that there are an infinite number of them, always in motion . -
John Dalton
Born in Eaglesfield, Cumbria, United Kingdom
He was the first physicist to explain atoms in terms of weight.By placing a glass in a large bowl of water, he saw that the glass that appeared empty was actually filled with hydrogen .The hydrogens pressure pushed against the water , preventing it from filling the glass. With this he realized atoms can not be created or destroyed , only combined and separated to form compounds . -
Death of John Dalton
In Manchester, United Kingdom -
J. J. Thompson
Born in Cheetham Hill, Manchester, United Kingdom
He discovered the negatively charged electron as a part of the atom earning him a Nobel prize. -
Ernest Rutherford
Born in Spring Grove, New Zealand
Reconstructed Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny, heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure. -
Nies bohr
Born in Copenhagen, Denmark
Bohr believed Electrons should move around the nucleus but only in prescribed orbits.Expanding on Rutherford’s theory ,he also realized that when electrons jump from one orbit to another with lower energy, a light quantum is emitted. -
Louis De Broglie
Born in Dieppe, France
Known for extending Einstein's ideas of duality of matter and the nature of electrons, Broglie’s experimental evidence showed that electrons must move around the nucleus of an atom -
Nobel Prize for J.J. Thompson
Discovered the negatively charged electron as a part of the atom earning him a nobel prize. -
Death of Ernest Rutherford
Dies in Cambridge, United Kingdom -
Death of J.J. Thompson
In Cambridge, United Kingdom -
Death of Niels Bohr
In Copenhagen, Denmark -
Death Louis De Broglie
In Louveciennes, France -
Quantum Mechanical Model of the Atom
The quantum mechanical model uses complex shapes of orbitals , volumes of space in which there is likely to be an electron.
