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Period: 370 to 460
Democritus
• lived - 460 BC died - 370 BC
• discovered
ATOMS:everything is mad up of themthey are eternalthey are invisibleso small they can’t be dividedthey fill up the whole space they’re in -
Period: to
Antoine Lavoisier
• born august 26 1743died may 8 1794
• he determined the law of conservation of matter, he did this by extensive experimentation
• antoine lavoisier discovered that matter is unable to be created nor destroyed -
Period: to
Joseph Proust
• born- 26th of september 1754 died- july 5th 1826
• proust’s theoryis that compunds alway contain the exact same proportion by the mass of elements -
Period: to
John dalton
• Born in 1766 Died at 77 years old
• Dalton based his work on Antoine Lavoisier’s work in the 1780’s.
• John Dalton discovered:
all elements are made up of atoms which are really small particlesatoms from each element are different this is including their massesa chemicle compound is formed when atoms from one element combine with atoms from another element in the same fixed proportionsatoms can’t be created or destroyed in a type of chemicle reaction -
Period: to
Michael Faraday
• born- september 22nd 1791died- august 25th 1867
• michael faraday made his discovery in the 1830’s, he discovered the idea of atoms having electrical components. to discover this he put 2 opposite electrodes in some water which contained a dissolved compound. -
Period: to
Joseph John Thomson
• born: 18/12/1856 died: 30/8/1940
• JJ thomon first discovered the electron during a series of experements which were ade for studying the nature of electric discharge in a high vacuume cathode-ray tube.
• the view of the atom was changed by having discovered the electron. JJ thomsons theory was that atoms wereade of other pieces electrons and protons.negative charged electrons embed an atom because of its posotive charge -
Period: to
Max Planck
• planck was born in germany on april 23rd 1858and died october 4th 1947
• he discovered that energy isn’t a continuous flowing entity but it is also arried in tiny units that are discontinued which henamed quanta, they are described as the pennies of the atomic world
• his theory formed a baseline for a new field of physics and quantum mechanics -
Period: to
Robert Millikan
• born: 22-3-1868died: 19-12-1953
• he performed the oil drop experiment and determined the charge of one electron and then using its known mass-charge ratio and was then able to calculate the mass on one electron -
Period: to
Ernest Rutherford
• born in the year of 1871died in the year of 1937
• his influence was joeseph john thomsons because ernest rutherford was the firstr graduate student at the cavendish labotory.
• ernest rutherford’s atomic theory was the atom being described as having a central positive neucleus which is surrounded by negative orbiting electrons
• he changed the views of the atom by finding out the atomis virtually made of large empty space -
Period: to
Frederick Soddy
• frederick soddy was born on 2nd of september 1877 and died on september 22nd 1956 in brighton
• fred soddy propsed tht the same eleents exist in all type of different forms. his theory of isotopes explains that different elements are ale to be chemically indistinguishable but can also have differeent atomic wieghts and charecteristics -
Period: to
Han Geiger
• born september 30 1882died september 24 1945
• he discovered alpha particles as being the neucleus of the helium atom
• they discovered that in any atom the nucleus keeps a very small volume at the centre occupied -
Period: to
Neil Bohr
• born- 1885 died - 1962
• Neils bohr assumed that electrons travel in certain stationary orbits.
• neils bohr changed our lives ecause he oon realised after working on the atomic bomb that it was dangerous so he changed from working with the atomic bomb to promoting atomic energy in a much more useful way. -
Period: to
Henry Moseley
• mosely born- in england on the 23rd of november 1887 died- 10th of august 1915 shot dead in gallipolli
• discovered that all atoms of a given element contain the same number of protons like in the neucleus
• his theory helped to figure out the mystery of what makes the atoms of one element different from the atoms of nother element -
Period: to
Walther Bothe
• born january 8 1891died february 8 1957
• walther bothe created a methos with a system for tracking collisions between electrons and electromagnetic quanta, he also studied individual atomic and neuclear processes. this work showed cosmic rays consist of huge particles and not merely photons.
• walther bothe’s discovery became very important in nucler physics his alpha ray bombardment study provided ceertain clues which james chadwick used to discover the neutron 2 years later. -
Period: to
James Chadwick
• born 20th of october 1891died- july 24th 1974
• chadwick established the atomic number by determining the number of proons in an atom he also discovered the fourth subatomic particle which was the neutron
• chadwick created a new era with his theory he was a leader in an investigation of both the milataryand the civilian applications of the discovery