copper

Name copper
Symbol Cu
Atomic Weight 63.546
Atomic Number 29
CAS ID 7440-50-8
Group Number 11
Group Name Coinage metal
Period Number 4
Origin of Name Latin, cuprum = "Cyprus."
Year Discovered Prehistoric
Discovery Credits Known to ancient civilizations.
Class Metallic
Color Copper, metallic
Standard State Solid at 77 F & 298 K
Description Reddish metal, malleable and ductile, with high electrical and thermal conductivities. Resistant to air and water but slowly weathers to green patina of basic carbonates. (Historically important alloy, bronze.) Used as wire for conducting electricity; coins; alloys, etc.

Diagnostic tests: 
On charcoal alone, or better with soda (Na2CO3), metallic copper can be reduced from most of its compounds. In the case of sulfides the powdered mineral is first roasted before adding the soda. 
With the borax bead test, it gives a green bead when hot, becoming blue when cold.
In solution, copper chloride gives a vivid blue flame test. Roasted ores and non-sulfide copper minerals will give the blue flame by adding HCl to the sample before heating.
In solution, the addition of excess amounts of NH4OH will produce an intense blue color to the sample.

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