A CHEMIST LOOKS AT

Most people look at a gold nugget and see a shiny metallic substance that can be melted down and made into jewelry. A chemist looks at a substance such as gold and visualizes the internal structure responsible for those external characteristics. Now that we have discussed some of the general features of atoms and elements, we can return to the model of solid, liquid, and gas structures presented in Section 2.1 and continue in our quest to visualize the particle nature of matter. 

The virtual chemical world is frighteningly big. One simple calculation showing how big this world is was based on a maximum of 30 atoms (which could be carbon, oxygen, nitrogen, or sulfur), which arrived at 10 possible core structures. If by whatever computational procedure were applied it took just 1 second to evaluate each of these virtual structures, it would take more than 10 years to complete this analysis. Clearly, such numbers teach only one lesson Virtual chemistry must be tamed before it can be applied usefully. There are clever ways to reduce the virtual chemical world to one that can be navigated in days, but we do not cover these here. The virtual chemical world as it is today is useful in helping a chemist look at structures that have never been seen before, to stimulate a new way of thinking about molecules. 

In Chapter 7 (A Chemist Looks At Zapping Hamburger with Gamma Rays) there is a discussion of how gamma radiation is used to kill bacteria in food. As indicated in the feature, there is concern on the part of some people that the irradiated food is radioactive. Why is this not the case If you wanted to make the food radioactive, what would you have to do ... 

Photc raphs used in title bars of A Chemist Looks At and Instrumental Methods features boxes Getty Images 2003... 

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