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THE ATOM
(MODELS) - Coggle Diagram
THE ATOM
(MODELS)
DALTON'S MODEL (1808) 
He imagined atoms as tiny, solid, indivisible spheres, like
microscopic billard balls.
Dalton's main ideas
• All matter is made up of tiny, indivisible particles called atoms.
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• In chemical reactions, atoms are rearranged but not
THOMSON'S MODEL(1897)
He proved that atoms were not indivisible as Dalton had thought. Thomson proposed
a new model (AKA the plum pudding)
According to Thomson
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• Negatively charged electrons are embedded within it, like raisins in a pudding.
• The positive and negative charges balance each other, making the atom neutral.
RUTHERFORD'S MODEL (1909)
Most particles passed straight through, but a few bounced back. This led Rutherford to propose a new model of the atom.
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BOHR'S MODEL(1913)
After Rutherford’s model, scientists could not explain why electrons did not fall into the nucleus. In 1913, the Danish physicist Niels Bohr proposed a new model that explained the stability of atoms.
Bohr's main ideas
1.- Electrons move around the nucleus, but only in specific orbits or energy levels.
2.- While electrons move in these orbits, they do not emit energy.
3.- Each orbit corresponds to a certain amount of energy: the closer it is to the nucleus, the lower the nergy
4.- When an electron absorbs energy, it jumps to a higher orbit (further from the nucleus).
5.- When an electron loses/releases energy, it falls back to a lower orbit (closer to the nucleus) and emits light