SCIENTISTS BY OLIVIA JOHNSON JOHN DALTON Chemist John

SCIENTISTS BY: OLIVIA JOHNSON

JOHN DALTON • Chemist John Dalton was born September 6, 1766, in Eaglesfield, England passed away July 26, 1844 in Manchester, England. • He invented the Atomic Theory

NIELS BOHR • Born on October 7, 1885, in Copenhagen, Denmark. Died on November 1892, in Copenhagen. • He made the Bohr Model

JJ THOMSON • J. J. Thomson was born on December 18, 1856, in Cheetham Hill, England. Rutherford died in Cambridge, England, on October 19, 1937 • Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, and thus he is credited with the discovery and identification of the electron also known as the plum pudding model

ERNERST RUTHERFORD • Ernest Rutherford was born August 30, 1871, in Spring Grove, New Zealand. Rutherford died in Cambridge, England, on October 19, 1937. • In 1911, Rutherford cooked up a new model of the atom in which all of the positive charge is crammed inside a tiny, massive nucleus about ten thousand times smaller than the atom as a whole

DMITRI MENDELEEV • Mendeleev was born Feb 8, 1834 in Verkhnie Aremzyani, Russian Empire. Died Feb 2, 1907 (at age 72) in St. Petersburg, Russian Empire • Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of their atomic weights". This became known as the Periodic Law.

ERWIN SCHRÖDINGER • Born on August 12, 1887, in Vienna, Austria. He died on January 4, 1961, in his home city. • Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom

ROBERT MILLIKAN • He was born March 22, 1968. Died December 19, 1953. • Robert Millikan determined the unit charge of the electron in 1909 with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. e = 1. 60 x 10 -19 coulombs

ANTOINE LAVOISIER • Antoine Laurent Lavoisier was born in Paris on Aug. 26, 1743. He died May 8, 1794. • He proposed the Combustion Theory which was based on sound mass measurements. He named oxygen. He also proposed the Law of Conversation of Mass which represents the beginning of modern chemistry.

JAMES CHADWICK • James Chadwick was born in Cheshire, England, on 20 th October, 1891. He died Jul 24, 1974 · Cambridge, United Kingdom • Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.

DEMOCRITUS • He was born 460 BC · Abdera, Greece. Died 370 BC. • "by convention bitter, by convention sweet, but in reality atoms and void“

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