ORIGIN OF ATOMS

• ATOM


  Basic unit of matter
• ATOMOS


  It means "uncuttable"
• DEMOCRITUS


  He presumed that matter is composed of tiny indivisible particles
• ELECTRON CONFIGURATION


  The assignment of all electrons in an atom into specific shells and subshells
• ANION/S


  A negatively charged ion
• ELECTRON


  A negatively charged particle
• CATHODE RAY TUBE


  A vacuum tube with two metal electrodes was used by Thomson in his experiment
• JSHAPED TUBE


  Used by dalton in experimenting with the composition of the atoms
• VALENCE ELECTRONS


  Electrons in the outermost energy level of an atom, involved in chemical bonding
• Valence


  Capacity, for atoms, valence pertains to the capacity of atoms to form bonds
• SPIN QUANTUM NUMBER


  The orientation of the electron spin
• Historical period during the development of the atomic theory

  • Ancient Greek philosophy
  • Emergence of alchemy
• Hubble/Cosmic Expansion


  Other galaxies are moving away relative to the Milky Way at a rate proportional to the distance
• Cosmic Wave Background


  An afterglow of radiation must have filled the universe
• Big Bang Nucleosynthesis


  Fusion of protons and neutrons, forming a nuclei
• Stellar Nucleosynthesis


  Responsible for the formation of heavy elements
• Lifespan of stars


  • Small
  • Medium-sized
  • Massive
• Nuclear Fusion Reactions


  • Exothermic reactions
  • Burning phases
• Dalton's Model/Solid Sphere Model (1803)


  "Matter as composed of atoms"
• Atoms of heavier elements are produced
• The Scanning Tunneling microscope is Made by John Dalton
• Dalton used a Scanning Tunneling Microscope
• Thomson's Model/Plum Pudding Model (1897)


  "Atoms were made of smaller subatomic particles"
• Plum Pludding Model is Proposed By Joseph John Thomson
• Plum Pludding Model discovered electrons weightless particles
• Thomson used CATHODE RAY TUBE in his experiment
• Rutherford's Gold-Foil Experiment


  • Discovered protons positively charged particles
  • Discovered alpha particles
• Rutherfold's Gold foil Experiment was Made by Ernest Rutherford
• Alpha Particles


  A very thin gold foil with a stream of atoms
• Nuclear Model


  • The atom consists of a dense positive center
  • Orbited by negatively charged electrons
• Nucleus is only 0.01pm compared to the atom (150pm)
• Bohr's Model


  The negatively charged electrons orbit small, positively charged particles
• Bohr's model was Made by Niels Bohr
• Quantum Mechanical Model


  • Describes the probability of finding electrons within given orbitals, or three-dimensional regions of space, within an atom
  • The farther the orbital is from the nucleus, the higher is the energy of the electrons
• Quantum Mechanical Model was Made by Ernest Schrodinger
• Atomic Number = Protons = Electrons
• Atomic Mass - Atomic Number = Neutrons
• Neutrons + Atomic Number = Atomic Mass