Bromine

Bromine is atom number 35 — every Bromine atom has exactly 35 protons in its center, and that number is what makes it Bromine and nothing else. Its symbol is Br. At room temperature it is a liquid.

Bromine (from Ancient Greek:βρῶμος, brómos, meaning "stench") is a chemical element with symbol Br, and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826.

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

Bromine sits in period 4, group 17 of the p-block. Its 35 electrons fill shells of 2, 8, 18, 7 — written as [Ar] 3d10 4s2 4p5. Its electronegativity is 2.96 on the Pauling scale, and pulling the first electron off takes 1139.9 kJ/mol. The outermost shell holds 7 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
Ionization energies (kJ/mol): 1139.9, 2103, 3470, 4560, 5760, 8550, 9940, 18600
Electron affinity: 324.537 kJ/mol · Electronegativity (Pauling): 2.96
Density: 3.1028 g/cm³ · melts 265.8 K · boils 332 K

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