65Tb158.925
Lanthanidef-block
Terbium
Element 65 on the periodic table, symbol Tb, group 3, period 6.
Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.
Appearance: silvery white
Properties
- Atomic Number
- 65
- Atomic Mass
- 158.9254 u
- Group
- 3
- Period
- 6
- Block
- f-block
- Category
- Lanthanide
- State at 25 °C
- Solid
- Melting Point
- 1,629 K · 1,355.9 °C
- Boiling Point
- 3,396 K · 3,122.9 °C
- Density
- 8.23 g/cm³
- Atomic Radius
- 175 pm
- Electronegativity
- 1.1
- Oxidation States
- +3
- Abundance in Crust
- 1.2 mg/kg
- Discovered
- 1843
- Discovered By
- Carl Gustaf Mosander
Electron Configuration
[Xe] 4f9 6s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f9
Ionisation Energies (kJ/mol)
- 1. 565.8
- 2. 1,110
- 3. 2,114
- 4. 3,839
Elements near Terbium
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.