Parts of an Atom

• Atoms are mostly open space 
• Atoms are composed of protons, electrons and neutrons
• Protons
  • Positive charged and are located in the nucleus of the atom
• Neutrons
  • No charge and located in the nucleus
• Electron
  • Negative charge and orbit the nucleus
• Atoms form all parts of matter
• Atoms combine to form compounds in a whole number ratio

(picture from http://www.chem4kids.com/files/atom_structure.html)

John Dalton (1766-1844)

• Atomic Theory
  • All matter is made of atoms. Atoms are indivisible and indestructible.
  • We now know this is not true, there are smaller parts to an atom
  • All atoms of a given element are identical in mass and properties
    • We also now know that this is not true not all atoms of a given element have identical mass
  • Compounds are formed by a combination of two or more different kinds of atoms
  • A chemical reaction is a rearrangement of atoms.
•  Who is this man and what is his significance?  This man is John Dalton and he came up with dalton's theory.
• WhWhat is smaller a molecule or an atom? An Atom is smaller
       What did dalton's theory state? Dalton's theory stated that all atoms are indistructable and all matter is made up of atoms and that all atoms are identical in mass and properties.
  In 1911 Ernest Rutherford carried out the gold foil expirement. This proved that there is a negatilvly charged elecron cloud, which was mostly empty space surronding the smaller, positivly charged nucleus.This experiment resulted in Rutherfords new theory of the atom that the atom was mostly empty space and that the mass of the atom was mostly located in the nucleus.
   what was dalton's famous experiment and what did it conclude?
   What are the charges and relative masses of the three main subatomic particles?   A neutron has a neutral charge and has approximately the same mass as a proton(1 amu).  A proton has a positve charge which is equal to the negative charge of an electrons are comparitively miniscule, with an insignificant mass.
  The Big Question: Who came up with Dalton's Theory?