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101
Democritus Theory
Atoms that are present in the atmosphere. These are about the atoms that are present in all the forms of existence; for instance, solid or liquid. The theory states that these atoms are all individually created and cannot be separated, no matter what scientific procedures are applied. -
John Dalton
All matter is made of atoms. Atoms are indivisible and indestructible.
All atoms of a given element are identical in mass and properties
Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms. -
J.J Thomson
When some materials are rubbed together they gain the ability to attract ot repel other materials. He used a glass tube which most of the air had been removed. He placed a metal disk on the ends. Wires connect them to a sorce of electrcity. When the current is turned on one was negativetly charge the other positive. This created a glowing beam. -
Hantaro Nagaoka
He didn't believe what J.J Thomson said was true for the positively charged atoms. -
Ernest Rutherford
Aimed a narrow beam of alpha particles at gold. The screen around the gold was made of a material that produced a flash of light when struck by fast moving alpha paricles. That the positive chrge if an atom is not evenly spread out it is concentrated in area called the nucleus. -
Neils Bohr
It looked like the solar systam with the planets revolveing around the sun. If an atom gains or loses energy the engergy of an electron can change. The possible energies an electron in an atm can have are called energy levels. -
Werner Heisenberg & Erwin Schrodinger
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James Chadwick
The neutron, a neutrally charged particle with the same mass as the proton
