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Thursday, February 21, 2013

Chemistry Form 4: Chapter 2 - Structure of an Atom

   
  • Atom consists of electrons surrounding a nucleus that contains protons and neutrons.
  • Electrons are arranged around the nucleus in energy levels or shells. 
  • The mass of an atom is concentrated in nucleus which contained the protons and neutrons.
  • The nucleus is positively charged because of the presence of protons which are positively charged and the neutrons are neutral.
  • The atom is neutral because the number of protons and the number of electrons are equal

 Subatomic particles
    Symbol
 Relative mass
    Relative   charged
   Position
Proton
P
1
+1

  Nucleus
Neutron
N
1
0
Electron
e-
  1/1837 » 0
-1
  Orbit

Symbol of Element



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