Xenon

Xenon is atom number 54 — every Xenon atom has exactly 54 protons in its center, and that number is what makes it Xenon and nothing else. Its symbol is Xe. At room temperature it is a gas.

Xenon is a chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas, that occurs in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.

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

Xenon sits in period 5, group 18 of the p-block. Its 54 electrons fill shells of 2, 8, 18, 18, 8 — written as [Kr] 4d10 5s2 5p6. Its electronegativity is 2.6 on the Pauling scale, and pulling the first electron off takes 1170.4 kJ/mol. The outermost shell holds 8 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6
Ionization energies (kJ/mol): 1170.4, 2046.4, 3099.4
Electron affinity: -77 kJ/mol · Electronegativity (Pauling): 2.6
Density: 5.894 g/L · melts 161.4 K · boils 165.051 K

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