CK-12 Physical Science - For Middle School

(Marvins-Underground-K-12) #1

6.1. How Elements Are Organized http://www.ck12.org


6.1 How Elements Are Organized


Lesson Objectives



  • Describe Mendeleev’s periodic table of the elements.

  • Give an overview of the modern periodic table of the elements.


Vocabulary



  • group

  • period

  • periodic table


Introduction


Scientists first started looking for a way to organize the elements in the 1700s. They were trying to find a method
to group together elements with similar properties. No one could come up with a good solution. It wasn’t until the
1860s that a successful method was devised. It was developed by a Russian chemist named Dmitri Mendeleev. He is
pictured inFigure6.1. You can learn more about him and his work at this URL: http://videos.howstuffworks.com/
science-channel/27862-100-greatest-discoveries-the-periodic-table-video.htm.


FIGURE 6.1


Dmitri Mendeleev developed the first periodic table of the elements in
1869.
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