Yttrium

Yttrium is atom number 39 — every Yttrium atom has exactly 39 protons in its center, and that number is what makes it Yttrium and nothing else. Its symbol is Y. At room temperature it is a solid.

Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a "rare earth element". Yttrium is almost always found combined with the lanthanides in rare earth minerals and is never found in nature as a free element.

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

Yttrium sits in period 5, group 3 of the d-block. Its 39 electrons fill shells of 2, 8, 18, 9, 2 — written as [Kr] 4d1 5s2. Its electronegativity is 1.22 on the Pauling scale, and pulling the first electron off takes 600 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 4d1
Ionization energies (kJ/mol): 600, 1180, 1980, 5847, 7430, 8970, 11190, 12450 … (12 published)
Electron affinity: 29.6 kJ/mol · Electronegativity (Pauling): 1.22
Density: 4.472 g/cm³ · melts 1799 K · boils 3203 K

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