Electrons and Chemical Reactions
Please explain what electrons have to do with chemical
Thanks for your question.
If you look at a Periodic Table of the Elements, you will learn that
elements in the same column have similar chemical properties. For example,
all of the elements in the first column (excluding hydrogen) are very highly
The reason elements in the same column have similar chemical properties is
because they have the same number of outer shell ("valence") electrons. For
example, all the highly reactive metals in the first column of the periodic
table have one valence electron; the elements in column two have two valence
electrons. The noble gases (in the column on the far right) have 8 valence
electrons (except for Helium, which has 2) and 8 (or 2) is the maximum
number -- so those elements tend to not react easily with other chemicals.
One of the best things that you can help your middle school students
understand is that it is the electrons -- specifically the outer shell,
valence electrons, that determine how an element will react chemically.
Many students get stuck on the number of protons determining whether an atom
is gold, or oxygen, or tin. And although that is true, it really the number
and arrangement of the electrons that determine how an element will react
Here are some websites with more information:
Todd Clark, Office of Science
US Department of Energy
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Update: June 2012