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(2000).iso/amsci01/tblib/readyrefs/www.periodic.lanl.gov/_themes/expeditn/expbul1a.gif){kind=small} | The Elements Lithium (Li), Sodium (Na), and Potassium (K) all formed oxides in the ratio of two atoms per oxygen atom: R2O |
| The Elements Beryllium (Be), Magnesium (Mg), and Calcium (Ca) all formed oxides in the ratio of one atom per oxygen atom: RO |
| Boron (B) and Aluminum (Al) formed R2O3 |
| Carbon (C) and Silicon (Si) formed RO2 |
Recognizing the patterns of combining ratios or "valency", Mendeleev created a table organized by placing elements with similar combining ratios in the same group. He arranged the elements within a group in order of their atomic mass.
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In 1869, the Russian chemist Mendeleev noted that the repeating patterns of behavior could be arranged in a sequence of elements giving rise to the "Periodic Table" of the elements. |
Special thanks to Dr. Paul Karol's Intro to Modern Chemistry for providing much of the information on this page.