Boron

Boron is atom number 5 — every Boron atom has exactly 5 protons in its center, and that number is what makes it Boron and nothing else. Its symbol is B. At room temperature it is a solid.

Boron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.

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

Boron sits in period 2, group 13 of the p-block. Its 5 electrons fill shells of 2, 3 — written as [He] 2s2 2p1. Its electronegativity is 2.04 on the Pauling scale, and pulling the first electron off takes 800.6 kJ/mol. The outermost shell holds 3 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p1
Ionization energies (kJ/mol): 800.6, 2427.1, 3659.7, 25025.8, 32826.7
Electron affinity: 26.989 kJ/mol · Electronegativity (Pauling): 2.04
Density: 2.08 g/cm³ · melts 2349 K · boils 4200 K

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