Niobium

Niobium is atom number 41 — every Niobium atom has exactly 41 protons in its center, and that number is what makes it Niobium and nothing else. Its symbol is Nb. At room temperature it is a solid.

Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology:Niobe, daughter of Tantalus since it is so similar to tantalum.

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

Niobium sits in period 5, group 5 of the d-block. Its 41 electrons fill shells of 2, 8, 18, 12, 1 — written as [Kr] 4d4 5s1. Its electronegativity is 1.6 on the Pauling scale, and pulling the first electron off takes 652.1 kJ/mol. The outermost shell holds 1 electron — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d4
Ionization energies (kJ/mol): 652.1, 1380, 2416, 3700, 4877, 9847, 12100
Electron affinity: 88.516 kJ/mol · Electronegativity (Pauling): 1.6
Density: 8.57 g/cm³ · melts 2750 K · boils 5017 K

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