Rule of noble gases in chemistry

The tool of the trade in chemistry - the periodic table

• Atoms consist of a positive atomic nucleus, which consists of protons and neutrons, of negative electrons that circle the nucleus on defined paths.
• The electrons are arranged on shells. If you go in Periodic table of the elements from top to bottom, a new shell is added with each row (called period). Going from left to right in the periodic table, there is always an additional electron in the outermost shell. The outermost shell is always fully occupied first before electrons are placed on a shell above.
• There can be a maximum of eight electrons on the outermost shell - hence the eight main groups in the periodic table. The eighth main group are the noble gases, all of which (with the exception of helium, which has only two electrons) have eight electrons on the outermost shell.
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What the noble gas rule says

• This so-called noble gas configuration with eight electrons on the outermost electron shell is very stable. The noble gas rule states that all elements strive for this noble gas configuration.
• This happens either by accepting or releasing electrons, i.e. by forming ions, or by the fact that atoms form bonds and the binding electrons share, in order to achieve the noble gas configuration reach.


Similarities of the atoms - the main group easily explained

The periodic table of the elements is divided into groups. This is not a coincidence because ...

• The noble gas rule does not apply strictly. Subgroup elements usually strive for 18 electrons on their outermost shell, which they have additional orbitals available. There are also electron deficiency compounds (a prominent example in the chemistry is the diborane), in which there are fewer electrons than required by the noble gas rule.
• The pursuit of the noble gas configuration determines the chemistry of the elements.