1. Atom
    The smallest particle of an element that retains its identity in a chemical reaction
  2. Scanning Tunneling Microscope
    An instrument used to generate images of individual atoms
  3. John Dalton
    English Chemist and schoolteacher who formulated a theory to describe the structure and chemical reactivity of matter in terms of atoms
  4. Democritus
    Greek philosopher who was among the first to suggest the existence of atoms
  5. Electrons
    Negatively charged subatomic particles
  6. Cathode Ray
    stream of electrons produced at the negative electrode of a tube containing a gas at low pressure
  7. Protons
    Positively charged subatomic particles
  8. Neutrons
    Subatomic particles with no charge
  9. Nucleus
    the central core of an atom, which is composed of protons and neutrons
  10. Atomic Number
    the number of protons in the nucleus of an atom of an element
  11. Periodic Table
    an arrangement of elements according to similarities in their properties
  12. Mass Number
    equals the number of neutrons plus the number of protons in an atom
  13. Group
    A vertical column of elements in the periodic table
  14. Isotopes
    atoms that have the same number of protons but different numbers of neutrons
  15. Atomic Mass Unit (amu)
    1/12 the mass of a carbon-12atom
  16. Atomic Mass
    weighted average mass of the atoms in naturally occurring sample of an element
  17. Period
    A horizontal row of the periodic table
Card Set
Prentice Hall Chpt. 4