Atomic Number
68
Erbium is a chemical element with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements.
68
167.26 u
lanthanide
solid
9.07 g/cm³
2, 8, 18, 30, 8, 2
Protons: 68 • Electrons: 68 • Neutrons: Varies by isotope
Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹²
1843 • Carl Gustaf Mosander