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Wednesday, 14 January 2015

The Noble Gases

Noble-gases

The elements of group VIII A (also known as group O) are known as noble gases,
Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and rarely Radon (Rn) are the elements of group VIII A.

They are all monoatomic gases. These gases are colorless, tasteless and odorless, and distinguished from all other elements, for their high chemical stability. 

This is due to their electronic configuration, with the exception of helium, split eight electrons in the outer layer (octet). All noble gases are present in the atmosphere in trace amounts, except argon, whose percentage by volume exceeds 0.9%. 

They are obtained as byproducts in the extraction of nitrogen and oxygen from the liquid.


Characteristics of Noble Gases (GROUP VIII A)


Names helium  Neon Argon  Krypton  Xenon  Radon

Symbol He  Ne Ar Kr Xe Rn

Atomic number 2   10   18 36 54  86

Electron configuration 1s2 2s22p6 3s23p6   4s24p6  5s25p6  6s26p6

Melting point (° C) -272  -249  -189  -157  -112 -110

Boiling point (° C) -269  -246  -186  -153  -107  -62