As you move through the simulation, try to put aside many of the modern concepts and theories that you have learned and now take for granted. Some of the ideas that chemists of this period held may appear strange to our eyes, but we should remember that we have more than 100 years of hindsight to our advantage. As one historian of chemistry puts it, "To view the works of great men of the past in the light of modern knowledge is perhaps to belittle their achievements." (2)

For instance, chemists of the 19th century did not differentiate between ionic and covalent compounds. The short time line below might put this period into perspective.   Periodic Table-1869   Lewis Structures 1920's   Neutron 1932       Inert Gases 1890's   Proton 1925   1810------------------------------>1870 The period of this simulation.