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Periodic table of the elements (view source)
Revision as of 01:53, November 7, 2009
, 01:53, November 7, 2009Organization of periodic table...
The '''periodic table of the elements''' is a diagrammatic tool to illustrate the scientific [[theory]] of [[periodicity]] in [[chemistry]], in which the [[element]]s have similar properties based on their position on the table. For example, the elements on the left of the table are all [[metal]]s. The table has a lot of predictive power, although there are many exceptions to the periodic properties.
The '''periodic table of the elements''' is a diagrammatic tool to illustrate the scientific [[theory]] of [[periodicity]] in [[chemistry]], in which the [[element]]s have similar properties based on their position on the table. For example, the elements on the left of the table are all [[metal]]s. The table has a lot of predictive power, although there are many exceptions to the periodic properties.
The periodic table was first developed by [[Russia]]n [[chemistry|chemist]] [[Dimitri Mendeleev]]. Its layout accurately arranges elements by their [[electron]] configuration, atomic number, and chemical properties. Using the structure he created, Mendeleev predicted the existence and properties of several yet-undiscovered elements; when those elements were discovered, his estimates proved to be quite accurate, vindicating his theory which had previously been criticised.
The periodic table was first developed by [[Russia]]n [[chemistry|chemist]] [[Dimitri Mendeleev]]. Its layout accurately arranges elements by their [[electron]] configuration, atomic number, and chemical properties. Using the structure he created, Mendeleev predicted the existence and properties of several yet-undiscovered elements; when those elements were discovered, his estimates proved to be quite accurate, vindicating his theory which had previously been criticized.
==Organization==
Elements in the periodic table are organized based on the number of [[electron]]s in their outermost [[electron shell]]. Since farther out shells have more [[orbital]]s, this means that there will be more elements in the lower rows of the periodic table than in the higher rows. For example, for [[principle quantum number] <i>n=1</i>, there is only one [[s-orbital]] available, which will fit only two electrons (due to the [[Pauli exclusion principle]], which states that no two electrons can have the same quantum numbers). Therefore, only two elements can be in the top row of the periodic table. As the [[principle quantum number]] increases, the number of electrons per shell rises, so the farther-down rows hold more elements.
The [[group number]] tells how many electrons an element has in its outermost electron shell. For example, every element in group 8A, the [[Nobel gases]], has its outermost electron shell completely full.
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==External Links==
==External Links==
*[http://www.learner.org/interactives/periodic/index.html Interactive Periodic Table] You've seen it before, but what do all those symbols and numbers really mean? You're about to find out.
*[http://www.learner.org/interactives/periodic/index.html Interactive Periodic Table] You've seen it before, but what do all those symbols and numbers really mean? You're about to find out.
* [http://www.sporcle.com/games/elements.php Name the elements in the Periodic Table!]
==The Periodic Table==
==The Periodic Table==