Lawrencium

Lawrencium is atom number 103 — every Lawrencium atom has exactly 103 protons in its center, and that number is what makes it Lawrencium and nothing else. Its symbol is Lr. At room temperature it is a solid.

Lawrencium is a synthetic chemical element with chemical symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series.

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

Lawrencium sits in period 7, group 3 of the d-block. Its 103 electrons fill shells of 2, 8, 18, 32, 32, 8, 3 — written as [Rn] 5f14 7s2 7p1. Its electronegativity is 1.3 on the Pauling scale, and pulling the first electron off takes 470 kJ/mol. The outermost shell holds 3 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 5f14 7p1
Ionization energies (kJ/mol): 470
Electron affinity: -30.04 kJ/mol · Electronegativity (Pauling): 1.3
Density: — · melts 1900 K · boils —

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