Gallium

Gallium is atom number 31 — every Gallium atom has exactly 31 protons in its center, and that number is what makes it Gallium and nothing else. Its symbol is Ga. At room temperature it is a solid.

Gallium is a chemical element with symbol Ga and atomic number 31. Elemental gallium does not occur in free form in nature, but as the gallium(III) compounds that are in trace amounts in zinc ores and in bauxite. Gallium is a soft, silvery metal, and elemental gallium is a brittle solid at low temperatures, and melts at 29.76 °C (85.57 °F) (slightly above room temperature).

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

Gallium sits in period 4, group 13 of the p-block. Its 31 electrons fill shells of 2, 8, 18, 3 — written as [Ar] 3d10 4s2 4p1. Its electronegativity is 1.81 on the Pauling scale, and pulling the first electron off takes 578.8 kJ/mol. The outermost shell holds 3 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1
Ionization energies (kJ/mol): 578.8, 1979.3, 2963, 6180
Electron affinity: 41 kJ/mol · Electronegativity (Pauling): 1.81
Density: 5.91 g/cm³ · melts 302.9146 K · boils 2673 K

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