Atomic Theorists How we got to where we are now
Law of Conservation of Mass Matter can’t be created or destroyed Who: Antoine Lavoisier When: 1785 Where: France
Law of Definite Proportions Compounds = Elements put together in fixed whole number ratios C + O 2 CO 2 Who: Joseph Proust When: 1797 Where: France
Law of Multiple Proportions Two elements can form more than one compoundelements compound The ratios of elements will be small whole numbers. Who: John Dalton Where: EnglandWhen: 1803
What: All matter is a combo of fire, air, earth or water When: 350 B.C. Where: Greece Who: Aristotle
Who: Democritus When: 400 B.C. Where: Greece What: Matter was made of indivisible substances he called atomos (1 st talk of the atom)
What: Solid Sphere Model (1 st atomic theory) Matter is made up of indivisible particles All atoms of a particular element are identical Different elements are composed of different kinds of atoms. Compounds are composed of atoms in specific ratios. Atoms are not created or destroyed in a reaction. When: 1805Where: England Who: John Dalton
How did Dalton do ? Matter is made up of indivisible particles No. Atoms can be divided All atoms of a particular element are identical No. Doesn’t account for isotopes Different elements are composed of different kinds of atoms. Yes! Compounds are composed of atoms in specific ratios. Yes! Atoms are not created or destroyed in a reaction. Yes!
What: Atoms aren't smallest particle Conducted experiment with a Cathode Ray Tube Particles had a negative charge (discovered electrons) Model = plum pudding When: 1897 Where: England Who: J.J. Thomson
Cathode Ray Tube
What: Experiments to determine mass of electron Conducted the oil drop experiment Verified that electron is negatively charged No new model Where: AmericaWhen: 1910 Who: Robert Millikan
Millikan Oil Drop Experiment
Who: Ernest Rutherford What: Conducted Gold Foil experiment Proved nucleus is dense, positively charged core of atom When: 1911 Where: America Model = Planetary Model
Rutherford’s Experiment Gold Foil Experiment
Who: Niels Bohr What: Pulsating Planetary Model Electrons can move between energy levels When: 1913 Where: Denmark
Who: James Chadwick What: Confirmed existence of neutron No new atomic model When: 1932 Where: England
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom is represented by this diagram? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom has the name “Planetary Model”? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom has the name “Solid Sphere”? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom has the name “Pulsating Planetary Model”? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick
Whose model of the atom has the name “Plum Pudding”? 1.Aristotle 2.Democritus 3.Dalton 4.Thomson 5.Millikan 6.Rutherford 7.Bohr 8.Chadwick