Cobalt

Cobalt is atom number 27 — every Cobalt atom has exactly 27 protons in its center, and that number is what makes it Cobalt and nothing else. Its symbol is Co. At room temperature it is a solid.

Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

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

Cobalt sits in period 4, group 9 of the d-block. Its 27 electrons fill shells of 2, 8, 15, 2 — written as [Ar] 3d7 4s2. Its electronegativity is 1.88 on the Pauling scale, and pulling the first electron off takes 760.4 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d7
Ionization energies (kJ/mol): 760.4, 1648, 3232, 4950, 7670, 9840, 12440, 15230 … (27 published)
Electron affinity: 63.898 kJ/mol · Electronegativity (Pauling): 1.88
Density: 8.9 g/cm³ · melts 1768 K · boils 3200 K

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