Presentation Transcript
Atomic Theory :1 Atomic Theory History of the Atom
History of the Atom :2 History of the Atom Democritus- lived around 300b.c.
Said that the smallest part of matter is an atom
Slide 3:3
History of the Atom :4 History of the Atom Aristotle- lived around 300b.c.
Said that matter was composed of 4 elements:
Earth
Wind
Fire
Water
Slide 5:5
History of the Atom :6 History of the Atom John Dalton- 1808
Said that:
Each element is made of atoms that are all alike
Different elements have atoms of different mass
Imagined atoms as tiny, solid spheres
Dalton’s Model :Dalton’s Model Tiny, solid spheres 7
Slide 8:8
History of the Atom :9 History of the Atom J. J. Thomson- 1897
Said that:
Atoms are positively charged spheres with electrons embedded in them
Thomson’s Model :Thomson’s Model Chocolate chip cookie model 10
Slide 11:11
History of the Atom :12 History of the Atom E. Rutherford – 1911
Said that :
Electrons orbit around a small, positively charged nucleus
Rutherford’s Model :Rutherford’s Model Positive nucleus surrounded by negative electrons 13
Slide 14:14
History of the Atom :15 History of the Atom Niels Bohr 1913
Said that:
Electrons move in specific energy levels around the positive nucleus
Bohr Model of the Atom :Bohr Model of the Atom Electrons in Energy Levels 16
Slide 17:17
The Present Model of the Atom :18 The Present Model of the Atom Electron cloud model
The position of an electron is impossible to predict, instead it forms a cloud of negative charge
Slide 19:19