Radium

Radium is atom number 88 — every Radium atom has exactly 88 protons in its center, and that number is what makes it Radium and nothing else. Its symbol is Ra. At room temperature it is a solid.

Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is almost colorless, but it readily combines with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (Ra3N2).

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

Radium sits in period 7, group 2 of the s-block. Its 88 electrons fill shells of 2, 8, 18, 32, 18, 8, 2 — written as [Rn] 7s2. Its electronegativity is 0.9 on the Pauling scale, and pulling the first electron off takes 509.3 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2
Ionization energies (kJ/mol): 509.3, 979
Electron affinity: 9.6485 kJ/mol · Electronegativity (Pauling): 0.9
Density: 5.5 g/cm³ · melts 1233 K · boils 2010 K

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