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Atomic Theory Timeline

Published on Nov 21, 2015

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PRESENTATION OUTLINE

ATOMIC THEORY TIMELINE

DEMOCRITUS' CONTRIBUTIONS

  • Greek Philosopher
  • First philosopher credited towards the progression of atomic theory
  • He was the first to name the atom, the atom

DEMOCRITUS' THEORY

  • The atom is the smallest particle
  • Nothing exists except atoms and empty space

DALTONS THEORY

  • Each element is composed of tiny indestructable particles called atoms
  • (Tiny, hard indivisible spheres)
  • All atoms if an element are identical
  • They have the same mass, volume, and other physical properties
  • Atoms combine in small whole number ratios to firm molecules of compounds

J.J THOMPSON'S CONTRIBUTIONS

  • Credited with the discovery of the electron

J.J THOMPSON THEORY

  • Found that the atom is breakable
  • The atoms structure has electrons suspended in a positivly charged field
  • It must have a positive charge to balance out the negative charge

THOMPSONS EXPERIMENT

  • A cathode ray with a positive and negative side
  • Two plates on the outside- positive and negative
  • The beam was angled to the positive side
  • This suggest that there is a negative charge

RUTHERFORD'S EXPERIMENT

  • Shot a alpha particle through gold foil
  • Most of the particles went straight through
  • Some particles bent
  • Only few bounced back

RUTHERFORD'S THEORY

  • The atom contains a tiny dense positive center called the nucleus
  • The nucleus is the entire mass if the atom
  • The electrons are dispersed in the space surrounding the nucleus
  • Discovered the proton and thr neutron
  • Proton has a positive charge- neutron has no charge

BOHR'S THEORY

  • Electrons travel around the nucleus in orbitals
  • Every orbital has its number of subshells
  • Each subshell can hold 2 electrons
  • The further the electron, the more energy it has
  • Moving up- excited state- moving down- ground state

SCHRODINGER'S ATOMIC THEORY

  • Developed an equation that predicts the probability of finding an electron
  • With a particular amount if energy at a particular location in an atom
  • Discovered the orbital
  • EAch orbital can hold 1,2,3, or 4 subshells
  • These are s,p,d, and f