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John Dalton:modern atomic theory
No experimentation, used laws to develop theory, conclusion- matters are made of atoms that are identical atoms that cannot be destroyed or rearranged in reactioncontribution-the modern atomic theory -
Joseph John Thomson:Leptons
Leptons are a family of elemental particles that includes the electron. Such as quark, make up protons and neutrons in the nucleus. Its a fermion, meaning it has a quantum spin of 0.5.Conclusion- discovered the leptons and its relationships with the atoms.contribution-leptons -
The Curies
Pierre Curie and his wife Marie Curie stated that radioactive materials cause atoms to break down spontaneously, releasing radiation in the form of energy and subatomic particles. -
Ernest Rutherford:positively charged nucleus
Gold foil experiment- shot a small positively charged particals were directed at a thin foil of gold atomsconclusion-the center of the atom is positive, atoms also contain empty spacescontribution-figured elctrons grouped around the nucleus -
Robert Milikan
He was an American experimental physicist, and Nobel laureate in physics for his measurement of the charge on the electron and for his work on the photoelectric effect. in 1909 Millikan worked on an oil-drop experiment in which they measured the charge on a single electron. His experiment measured the force on tiny charged droplets of oil suspended against gravity between two metal electrodes. -
Neils Bohr:Enregy levels
explained that electrons travel around the nucleus in exact paths. These paths are always at a certain level away from the nucleus. He also stated that electrons cannot travel in between each path, but they can hop from one path to another.contribution- energy levels -
Arnold Sommerfeld
In 1915, Sommerfeld made a major contribution to Niels Bohr's atomic theory by extending the theory to include elliptical paths for electrons. -
Irving Langmuir
Irving's theory was that he could name the atoms that can lose an electrin and bond; covalent. Also his theory discussed the chemical forces between different substances. -
Erwin Schrodinger
Erwin developed mathematical equations to describe the motion of electrons in atoms. His model was developed into a electron cloud. -
James Chadwick:neutral neutrons
experiment- tried to simplify as much as possible the particles, performed radiationconclusion- particles had no electric charge, showig they were neutral particlescontribution- concluded that particles of a beam from alpha particles hitting beryllium carried no electric charge they were neutral particles called neutrons -
Werner Heisenberg
One of his most memorable discoveries is the Uncertainty Principle. He said this means that electrons do NOT travel in neat orbits. Also, all electrons that contain photons will then change momentum and physics -
Murray Gell-Mann:Quarks
proposed the existence of a new level of elementary particles - quarks. These little bits of matter which when used kind of as building blocks of protons and neutrons, helped explain some complex chemical substances.contribution-helped to lay the base for our understanding of the components that make up matter
