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Dalton Model
British chemist John Dalton cuncluded that each element is made of atoms that are all alike. Also, that different elements have atoms of different mass. He imagined atoms as tiny, solid balls. The main ideas of his theory is that all matter is composed of atoms, which are indivisible. All atoms of a given element are alike in mass and all other respects. Atoms are indestructible and perserve thier identities in all chemical reactions. -
Thomson Model
British scientist J.J Thomson discovered the electron. He later proposed a new model, suggesting that an atom is a positively charged sphere with electrons embedded in it. His model could be described as looking like a muffin with berries or raisins scattered through it. The atom is a sphere of positively charged material with tiny negatively charged eletrons inside it, like currants in a plum pudding. -
Nagaoka Model
Japanese physicist Hantaro Nagaoka proposed a model of the atom that had a large sphere in the center with a positive charge. His model showed the electrons revolving around this sphere like planets around the sun. -
Rutherford Model
British physicist Ernest Rutherford concluded that the atom is mostly empty space. Eletrons orbit randomly around a small, positively charged nucleus. The positively charged material is a tiny nucleus in the centre. The electrons move abouit this is definte spherical orbits. The rest is empty space. -
Bohr Model
Danish physicist Niels Bohr proposed a model that showed eletrons moving in specific layers, or shells, rather than randomly. He said that atoms absorbed or give off energy when the electrons move from one shell to another. -
The Present Model
The current atomic model results from work done from the 1920s to the present. Electrons from a negatively charged cloud around the the nucleus. It is impossible to determine exaclly where an eletron is at a given time. -
Works Cited
http://www.kyrene.org/Staff/mijohns/atomic_structure_website/images/thomsonatom.png http://www.kyrene.org/Staff/mijohns/atomic_structure_website/images/thomsonatom.png http://www.xtimeline.com/__UserPic_Large/55624/evt100319183900346.bmp http://faculty.virginia.edu/consciousness/images/rutherford%20model.gif
