Copper

Copper is atom number 29 — every Copper atom has exactly 29 protons in its center, and that number is what makes it Copper and nothing else. Its symbol is Cu. At room temperature it is a solid.

Copper is a chemical element with symbol Cu (from Latin:cuprum) and atomic number 29. It is a soft, malleable and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a reddish-orange color.

Summary from the source dataset, derived from Wikipedia (CC BY-SA 3.0) · original article

Copper sits in period 4, group 11 of the d-block. Its 29 electrons fill shells of 2, 8, 18, 1 — written as [Ar] 3d10 4s1. Its electronegativity is 1.9 on the Pauling scale, and pulling the first electron off takes 745.5 kJ/mol. The outermost shell holds 1 electron — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Ionization energies (kJ/mol): 745.5, 1957.9, 3555, 5536, 7700, 9900, 13400, 16000 … (29 published)
Electron affinity: 119.235 kJ/mol · Electronegativity (Pauling): 1.9
Density: 8.96 g/cm³ · melts 1357.77 K · boils 2835 K

Values exactly as published — see where the data comes from.