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Gold (play /'go?ld/) is a chemical element with the symbol
Au (from Latin: aurum "gold") and an atomic number of 79. Gold
is a dense, soft, shiny metal and the most malleable and
ductile metal known. Pure gold has a bright yellow color and
luster traditionally considered attractive, which it maintains
without oxidizing in air or water. Chemically, gold is a
transition metal and a group 11 element. With exception of the
noble gases, gold is the least reactive chemical element
known. It has been a valuable and highly sought-after precious
metal for coinage, jewelry, and other arts since long before
the beginning of recorded history.
Gold resists attacks by individual acids, but it can be
dissolved by the aqua regia, so named because it dissolves
gold. Gold also dissolves in alkaline solutions of cyanide,
which have been used in mining. Gold dissolves in mercury,
forming amalgam alloys. Gold is insoluble in nitric acid,
which dissolves silver and base metals, a property that has
long been used to confirm the presence of gold in items.
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