Dysprosium

Dysprosium is atom number 66 — every Dysprosium atom has exactly 66 protons in its center, and that number is what makes it Dysprosium and nothing else. Its symbol is Dy. At room temperature it is a solid.

Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime.

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

Dysprosium sits in period 6, group 3 of the f-block. Its 66 electrons fill shells of 2, 8, 18, 28, 8, 2 — written as [Xe] 4f10 6s2. Its electronegativity is 1.22 on the Pauling scale, and pulling the first electron off takes 573 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 4d10 5p6 6s2 4f10
Ionization energies (kJ/mol): 573, 1130, 2200, 3990
Electron affinity: 33.96 kJ/mol · Electronegativity (Pauling): 1.22
Density: 8.54 g/cm³ · melts 1680 K · boils 2840 K

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