Chromium

Chromium is atom number 24 — every Chromium atom has exactly 24 protons in its center, and that number is what makes it Chromium and nothing else. Its symbol is Cr. At room temperature it is a solid.

Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.

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

Chromium sits in period 4, group 6 of the d-block. Its 24 electrons fill shells of 2, 8, 13, 1 — written as [Ar] 3d5 4s1. Its electronegativity is 1.66 on the Pauling scale, and pulling the first electron off takes 652.9 kJ/mol. The outermost shell holds 1 electron — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Ionization energies (kJ/mol): 652.9, 1590.6, 2987, 4743, 6702, 8744.9, 15455, 17820 … (24 published)
Electron affinity: 65.21 kJ/mol · Electronegativity (Pauling): 1.66
Density: 7.19 g/cm³ · melts 2180 K · boils 2944 K

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