69Tm168.93422
Thulium
Lanthanide
Solid at STP
Period 6Block FDiscovered 1879
[Xe]6s2 4f13
Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.
📖 Read more on Wikipedia →Atomic Properties
| Atomic Number | 69 |
| Atomic Mass | 168.93422 u |
| Electron Configuration | [Xe]6s2 4f13 |
| Oxidation States | +3 |
| Electronegativity | 1.25 (Pauling) |
| Atomic Radius | 227 pm |
| Ionization Energy | 6.184 eV |
| Block | F |
Physical Properties
| Appearance | silvery gray |
| Standard State | Solid |
| Melting Point | 1818 K (1544.8 °C) |
| Boiling Point | 2223 K (1949.8 °C) |
| Density | 9.32 g/cm³ |
| Molar Heat | 27.03 J/(mol·K) |
| CPK Color | #00D452 |
Classification
| Category | Lanthanide |
| Group Block | Lanthanide |
| Period | 6 |
| Block | F |
Discovery
| Year Discovered | 1879 |
| Discovered By | Per Teodor Cleve |
| Electron Shells | 2, 8, 18, 31, 8, 2 |