1. The History of Chemistry Eleven big ideas Chemistry Mr. Bimber

2. Democritus: Greek Philosopher (2500 B.C.) Made the word atom based on Greek word for indivisible.

3. John Dalton: England, early 1800s. Scientific theory of atoms: Element are made of atoms. All atoms of the same element are the same. Different elements atoms are different. Compounds are made of elements in definite ratios. Chemical reactions regroup atoms.

4. Dmitri Mendeleev: Russia, late 1800s. Created the first modern Periodic Table. Shows repeating (periodic) element patterns Elements arranged by atomic mass. Predicted properties of elements not known yet.

5. Henry Moseley: Britain, early 1900s. Died young in WW I. Fixed Mendeleevs Periodic Table: Arranged elements by atomic number, not atomic mass.

6. J.J. Thomson: Britain, early 1900s. Discovered electrons with negative charge Scattered like plums in a pudding. Measured charge on an electron. Cathode ray tube experiments.

7. Rutherford: Canada, early 1900s. Atoms heavy positive core: nucleus. Atoms heavy positive core: nucleus. Radioactive gun aimed at gold foil experiments.

8. Niels Bohr: Denmark, early 1900s. Mechanical model of the atom: electrons orbit the nucleus like planets around the sun.

9. Max Planck: Germany, early 1900s. Energy comes in tiny packets, called quanta. Quantum Theory changed Bohrs mechanical atom model into the quantum mechanical model.

10. Einstein: Germany, then US. Early 1900s. e=mc 2 energy equals mass times the speed of light squared. In other words, matter is energy.

11. Werner Heisenberg: Germany, 1900s. The Uncertainty Principle. you can't tell both location and energy of a subatomic particle, because finding one changes the other.

12. Louis DeBroglie France, mid 1900s. Atom parts are both particle and wave. His equations predict dual behavior of everyting, from protons to planets.

13. Chemistry History: Democritus : atom Democritus : atom Dalton: 5 part atomic theory Dalton: 5 part atomic theory Mendeleev &/or Moseley: periodic table Mendeleev &/or Moseley: periodic table Thomson: Plum Pudding theory/electrons Thomson: Plum Pudding theory/electrons Rutherford: Nucleus Rutherford: Nucleus Bohr: Mechanical Quantum Mech. Model Bohr: Mechanical Quantum Mech. Model Planck: Quantum Theory Planck: Quantum Theory Einstein: e = mc 2 (matter is energy) Einstein: e = mc 2 (matter is energy) Heisenberg: Uncertainty Principle Heisenberg: Uncertainty Principle De Broglie: Wave – Particle Dual Reality. De Broglie: Wave – Particle Dual Reality.