Copper
Definition and meaning of Copper in chemistry.
![Copper element card: symbol Cu, atomic number 29, atomic mass 63.546, electron configuration [Ar] 3d¹⁰ 4s¹, oxidation states +2, Transition metal, group 11, period 4, solid at room temperature.](/assets/images/terms/copper-chemical-element.webp)
Copper is a transition metal with the chemical symbol Cu and atomic number 29. This element is highly ductile and malleable, meaning it easily stretches into wire or hammers into thin sheets. It conducts heat and electricity exceptionally well, making it vital for modern power grids.
In more detail
Copper sits in group 11 of the periodic table. It is one of the few metals found in nature in a pure, usable form. Freshly exposed, pure copper has a distinct pinkish-orange color.
Over time, the metal reacts with oxygen, water, and carbon dioxide (CO2) in the air. This slow chemical reaction creates a protective green surface layer. We call this green layer a patina, and it consists of copper carbonate.
A common student misconception is that this green color means the metal has ruined or rusted like iron. In truth, this layer actually shields the inner metal from further damage. Copper forms many different chemical compounds and coordination salts.
It usually takes a +1 or +2 oxidation state when dissolved in water solutions. The metal is widely distributed throughout the Earth's crust. It is most often found as sulfide minerals like chalcopyrite and chalcocite.
Workers heavily mine, crush, and melt these mineral ores for modern commercial applications. Copper features a unique electron structure. It possesses a completely full d-subshell and a single s-electron.
This specific electron arrangement lets its valence electrons move freely, making copper an outstanding conductor of heat and electricity. Among all pure metals, only silver conducts electricity better than copper.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Cu |
| Atomic number | 29 |
| Atomic mass | 63.546 u |
| Category | Transition-Metal |
| Melting point | 1084.62 °C (1984.32 °F) |
| Year discovered | Known since antiquity (c. 9000 BC) |
Factories stretch pure copper into long wires for global electrical systems. Workers use these reliable wires to build major power transmission lines and everyday residential circuits. Copper is always the best choice because it conducts electricity far better than any other affordable, non-precious metal.
Frequently asked questions
Why does copper turn green over time?
It reacts with oxygen, water, and carbon dioxide in the air. This chemical reaction forms a thin protective layer of green copper carbonate.
What is the difference between brass and bronze?
Both of these mixtures are copper alloys. Brass is made of copper and zinc, while bronze is made of copper and tin.
Why does copper not dissolve in hydrochloric acid?
Copper has a low reactivity and sits below hydrogen in the activity series. Therefore, it cannot displace hydrogen gas from a standard acid.
Related terms
Sources & references
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