Periodic Table
29
Cu
63.546
Copper
Transition MetalConfig exception (3d¹⁰4s¹); Cu²⁺ blue; excellent conductor.
Electronic Configuration
[Ar] 3d¹⁰ 4s¹or1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹
Electron shells
2e⁻n=1
8e⁻n=2
18e⁻n=3
1e⁻n=4
Properties
Atomic number
29
Atomic mass
63.546 u
Category
Transition Metal
Block / Group / Period
d · 11 · 4
Valence electrons
1
Oxidation states
+1, +2
Electronegativity
1.9
Atomic radius
145 pm
Ionization energy
745 kJ/mol
Electron affinity
118 kJ/mol
Melting point
1358 K / 1085 °C
Boiling point
2835 K / 2562 °C
Density
8.96 g/cm³
State at 25 °C
solid
JEE / NEET notes
- Electronic config exception: [Ar]3d¹⁰4s¹ (fully-filled stability).
- Cu²⁺ blue (hydrated); anhydrous CuSO₄ white → blue with water.
- Fehling/Benedict: Cu²⁺ → red Cu₂O (test for reducing sugars/aldehydes).
- Cu⁺ is colourless & diamagnetic (3d¹⁰); disproportionates in water.
Exceptions
- • 3d¹⁰4s¹ configuration (not 3d⁹4s²).
Flame test
Bluish-green / green
Ores & extraction
Ores: Copper pyrites (CuFeS₂), Cuprite (Cu₂O), Malachite
Extraction: Roasting copper pyrites then Bessemerisation (self-reduction).
Uses
Electrical wiring · Alloys (brass, bronze) · Coinage · Fungicides
Important compounds
CuSO₄·5H₂O (blue vitriol)Cu₂OCuCl₂Cu(OH)₂
Personal Notes
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