Atomic Timeline

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Joseph Proust

1754 - 1856

Joseph taught a chemistry class at Sergovia and the University. He conducted many tests on chemicals such as copper. Joseph believes each object has its own elemental characteristics. The Objects elements will always stay the same no matter what the size is.

John Dalton

1766 - 1844

John was a British scientist. He had 4 theories, he thought that all matter consists of tiny particles. Atoms are indestructible and unchangeable. Elements are characterized by the mass of there atoms. When Elements react, their atoms combine in simple ratios.

Amedeo Avogado

1776 - 1856

In 1801 Amedeo was assigned secretary to the prefecture of the department of Eridano. He was very interested in philosophy in 1800 he began to study Math and Science. In 1811 Amedeo wrote an article on Molecules and Atoms in detail about there differences. He had wrote that Dalton had confused Molecules and Atoms. The atoms in nitrogen and oxygen are really just molecules containing two atoms each. Avogadro though that an equal amount of volume for all of the gases are the same temperature and the pressure contain the same number of molecules, which then became known as Avogadro's Principle

Dmitri Mendeleev

1834 - 1907

Dmitri arranged the elements into 7 groups with similar properties. His periodic table is one of the most important chemical discoveries of the nineteenths century. The first edition of Osnovy Khimii(periodic table) is extremely rare as only about six copies exist in the US.

JJ Thomson

1856 - 1940

Thomson suggested that electrons are 1000 times smaller than atoms. This lead him to discover cathode rays.
Thomson tried to put ionized neon through a magnetic and an electric field and measure its deflection by placing a photographic plate in its path.
In 1905 he discovered the radioactivity in Potassium.
In 1906 Thomson discovered hydrogen only has one electron per atom.

Marie Curie

1867 - 1934

Curie discover Polonium and Radium. Curie also found that the element thorium has the same emission characteristics as uranium.

Ernest Rutherford

1871 - 1937

Rutherford studied under J.J Thomson. He was one of the first to design original experiments on high frequency.
Rutherford experimented using gold foil, he tried to get the gold atoms to deflect off the tin foil. When some atoms bounced off, he discovered nucleus.

Hans Geiger

1882 - 1945

In 1928 Geiger helped invent the, Geiger Counter. This machine detected the alpha particles. Later this machine helped Geiger and is co-inverter Ernest Rutherford to help their studies on radiation.

Niels Bohr

1885 - 1962

Niels Bohr was born, raised, educated and later died in Copenhagen, Denmark. Bohr worked for JJ Thomson in England in 1911. He discovered that electrons in atoms are arranged by energy levels.

Enrico Fermi

1901 - 1954

Fermi created a nuclear reactor. He contributed to the development of the Quantum Theory. The nuclear Reaction was conducted to try and split an atom without creating an explosion.