Manganese

Manganese is atom number 25 — every Manganese atom has exactly 25 protons in its center, and that number is what makes it Manganese and nothing else. Its symbol is Mn. At room temperature it is a solid.

Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in combination with iron, and in many minerals. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels.

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

Manganese sits in period 4, group 7 of the d-block. Its 25 electrons fill shells of 2, 8, 13, 2 — written as [Ar] 3d5 4s2. Its electronegativity is 1.55 on the Pauling scale, and pulling the first electron off takes 717.3 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d5
Ionization energies (kJ/mol): 717.3, 1509, 3248, 4940, 6990, 9220, 11500, 18770 … (25 published)
Electron affinity: -50 kJ/mol · Electronegativity (Pauling): 1.55
Density: 7.21 g/cm³ · melts 1519 K · boils 2334 K

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