Joseph JohnJoseph JohnThompsonThompson

By: Cory Bair, Nick Nyce, Nick Shizzle

HistoryHistory

In 1987 he discovered the electron in a series of In 1987 he discovered the electron in a series of experiments. These experiments were to study experiments. These experiments were to study the electrons discharge in a high-vacuum the electrons discharge in a high-vacuum cathode ray tube.cathode ray tube.

TheoryTheory

The particle inside a positive The particle inside a positive charged matter were charged matter were negative. He called these negative. He called these particles electrons.particles electrons.

Helpful TheoriesHelpful Theories Dalton’s-Dalton’s theory helped out because it Dalton’s-Dalton’s theory helped out because it

stated that all elements are made up of atomsstated that all elements are made up of atoms Thomson’s helped Rutherford’s theory because Thomson’s helped Rutherford’s theory because

it helped him with more experimentation. it helped him with more experimentation. Rutherford found that Thomson was initiallyRutherford found that Thomson was initially wrong.wrong.

Theories-Experiments Theories-Experiments Rutherford performed many experiments with radioactive Rutherford performed many experiments with radioactive

alpha particles.alpha particles. Rutherford created the atom.Rutherford created the atom.

J.J. Thomson created the electron J.J. Thomson created the electron

Thomson found that the mysterious glowing stream Thomson found that the mysterious glowing stream would bend toward a positively charged electric plate. would bend toward a positively charged electric plate.

Thomson theorized, and was later proven correct, that Thomson theorized, and was later proven correct, that the stream was in fact made up of small particles, pieces the stream was in fact made up of small particles, pieces of atoms that carried a negative charge. These particles of atoms that carried a negative charge. These particles were later named electrons. were later named electrons.

RutherfordRutherford Rutherford proposed a revolutionary view of the Rutherford proposed a revolutionary view of the

atom. He suggested that the atom consisted of a atom. He suggested that the atom consisted of a small, dense core of positively charged particles small, dense core of positively charged particles in the center (or nucleus) of the atom, in the center (or nucleus) of the atom, surrounded by a swirling ring of electrons. surrounded by a swirling ring of electrons.

The nucleus was so dense that the alpha The nucleus was so dense that the alpha particles would bounce off of it, but the electrons particles would bounce off of it, but the electrons were so tiny, and spread out at such great were so tiny, and spread out at such great distances, that the alpha particles would pass distances, that the alpha particles would pass right through this area of the atom. right through this area of the atom.

Rutherford’s ExampleRutherford’s Example Gold FoilGold Foil The atom resembled a tiny solar system The atom resembled a tiny solar system

with the positively charged nucleus always with the positively charged nucleus always at the center and the electrons revolving at the center and the electrons revolving around the nucleus.around the nucleus.

                                                                                                                  

ElectronsElectrons

Thomson discovered electrons from his Thomson discovered electrons from his work with a nineteenth century scientific work with a nineteenth century scientific curiosity: the cathode ray tube.curiosity: the cathode ray tube.

AtomsAtoms Atoms are very small.Atoms are very small. Atom contains one Electron, Proton, Neutron.Atom contains one Electron, Proton, Neutron. Atoms of different elements are characterized by their number of Atoms of different elements are characterized by their number of

protons.protons. The number of protons are constant for all atoms of a single The number of protons are constant for all atoms of a single

element; the number of neutronselement; the number of neutrons and electrons can vary and electrons can vary

Works CitedWorks Cited

http://www.visionlearning.com/library/modhttp://www.visionlearning.com/library/module_viewer.php?mid=50ule_viewer.php?mid=50