Monday 20 June 2011

The Stability of Elements


Let we see the atomic structure of noble gases. They are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). Their atomic number are respectively 2, 10, 18, 36, 54 and 86, so that the electron configuration of noble gas atomic are :
He : 2
Ne : 2 8
Ar : 2 8 8
Kr : 2 8 18 8
Xe : 2 8 18 18 8
Rn : 2 8 18 32 18 8
Except helium the noble gas has eight valence electrons that form four electron pairs to result stability. The system of electron configuration with eight valence electron named octet rule. Helium only has two valence electrons, so that it form an electron pair only. This system named duplet rule. If the atoms of an element has octet or duplet system of it electron configuration, this element has high stability like noble gases. For this reason the unstable elements tend to reach duplet or octet system by electron configuration changing.

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