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Friday, October 9, 2009

Periodically Speaking


So, how do chemists keep all those elements straight? They use the Periodic Table of the Elements, like the one shown above. You can download and print your own larger copy here (You will need a Google or Gmail account to do this; you can create one for free). Every one of the chemical elements has its own box, with the number, symbol, and mass (weight). But why does it have this funny shape, especially near the top? The elements were originally put arranged into columns and rows according to how they behave chemically. For example, F (fluorine), Cl (chlorine), and Br (bromine) all form similar types of compounds. The same is true of Li (lithium), Na (sodium), and K (potassium). But this arrangement doesn't work out perfectly, so for a long time, scientists didn't fully understand why some elements went where they did. In the early 1900's, physicists and chemists were able to better explain how electrons were distributed within an atom, and this explained everything about the shape of the Periodic Table!
The Periodic Table is one of the most famous illustrations in science, and people have a lot of fun with it. Here are some other Periodic Tables you might want to look at:
and there's someone who has made an actual table using the Periodic Table!

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