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| Model of an Atom | 
An atom is a particle of matter that uniquely defines 
achemical element.   An atom consists of a central 
nucleus that is usually surrounded by  one or more 
electrons.  Each electron is negatively charged. 
The nucleus is  positively charged, and contains 
one or more relatively heavy particles  known 
as protons and neutrons.
 Kinds of Atom
 Solid Sphere Model or
Solid Sphere Model or      Billiard Ball Model
proposed by John Dalton
Raisin Bun Model
proposed by J.J. Thomson
Nuclear Model
proposed by Ernest Rutherford
 
 Bohr Model or
Orbit Model
proposed by Neils Bohr
Electron Cloud Model or
Quantum Mechanical Model
proposed by Louis de Broglie
& Erwin Schrodinger



