Editing Period 3 element (section)

=== Aluminium ===
{{Main|Aluminium}}
''Aluminium'' (symbol '''Al''') or ''aluminum'' ([[American and British English spelling differences#Different spellings for different pronunciations|American English]]) is a silvery white member of the [[boron group]] of [[chemical element]]s and a [[p-block metal]] classified by some chemists as a post-transition metal.<ref name=Huheey>Huheey JE, Keiter EA & Keiter RL 1993, ''Principles of Structure & Reactivity,'' 4th ed., HarperCollins College Publishers, {{ISBN|0-06-042995-X}}, p.&nbsp;28</ref> It is not soluble in water under normal circumstances. Aluminium is [[Abundance of elements in Earth's crust|the third most abundant element]] (after [[oxygen]] and [[silicon]]), and the [[element abundance|most abundant metal]], in the [[Earth's crust]]. It makes up about 8% by weight of the Earth's solid surface. Aluminium metal is too reactive chemically to occur natively. Instead, it is found combined in over 270 different [[mineral]]s.<ref>{{cite web|publisher=Science is Fun|author=Shakhashiri, Bassam Z.|url=http://scifun.chem.wisc.edu/chemweek/Aluminum/ALUMINUM.html|title=Chemical of the Week: Aluminum|access-date=2007-08-28|archive-url=https://web.archive.org/web/20070906175512/http://scifun.chem.wisc.edu/CHEMWEEK/Aluminum/ALUMINUM.html|archive-date=2007-09-06|url-status=dead}}</ref> The chief [[ore]] of aluminium is [[bauxite]].

Aluminium is remarkable for the metal's low [[density]] and for its ability to resist [[corrosion]] due to the phenomenon of [[Passivation (chemistry)|passivation]]. Structural components made from aluminium and its [[aluminium alloy|alloys]] are vital to the [[aerospace]] industry and are important in other areas of [[transport]]ation and structural materials. The most useful compounds of aluminium, at least on a weight basis, are the oxides and sulfates.