Atomic Structure

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Atomic Structure Powered By Docstoc
					   The building blocks of matter
Is it really the smallest thing out
                             there?
 The smallest particle of an element that
 retains the properties of that element
  • These are mostly chemical properties, not
   physical properties
 Particlesof matter that make up atoms
 Smaller than atoms themselves
 Behave differently than whole atoms
           charged particles found in the
 Positively
 nucleus of the atom
          with no charge found in the
 Particles
 nucleus of the atom
 Thecentral core of the atom
 Composed of protons & neutrons
  • it has a positive charge
 Held   together by the strong nuclear force
   • One of the four fundamental forces in
     the universe
 It contains almost all of the mass of the
  atom (very dense)
 It is a very small percentage of the
  volume of the atom
   • Marble in a football stadium
 As the nucleus gets larger, it becomes
  harder to create and more unstable
   • Why?
 Negatively charged particles found
 outside the nucleus in an area known as
 the “electron cloud”
                       Relative
Particle Symbol Charge
                        Mass
                           1
Electron   e-     -1     1836

Proton     p+     +1      1

Neutron    n0     0       1
 The   number of protons an atom contains
 Found on the periodic table
 The number of protons identifies the
  atom
   • Atoms of different elements will have
     different number of protons and
     different atomic numbers
 Whole atoms are electronically neutral
  • They must have the same number of protons
   (positive charge) and electrons (negative
   charge)
 Theatomic number is also the number of
 electrons an atom contains
 An (overwhelmingly) large majority of the
  mass of an atom is located in the nucleus
  • Protons & Neutrons are in the nucleus
 Mass Number is the sum of the number of
  protons and the number of neutrons
 Atoms  that have the same number of
  protons, but different number of neutrons
 They are the same element with a
  different mass
  • Same atomic number
  • Different mass numbers
 Element    Name – Mass Number
  • Oxygen-16
     8 protons/8 neutrons
  • Chlorine-35
     17 protons/18 neutrons
  • Uranium-238
     92 protons/146 neutrons
A
    X
         X: elementalsymbol
         Z: Atomic Number
         A: Mass Number




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posted:11/8/2012
language:English
pages:15