Technetium (Tc)
Technetium (Tc) is element 43 of the periodic table, a transition metal in period 5 and group 7. It has no stable isotope and no standard atomic weight; 98 is the mass number of its longest-lived isotope. At room temperature it is a solid; it melts at 2156.85 °C and boils at 4264.85 °C.
| Atomic number | 43 |
|---|---|
| Symbol | Tc |
| Standard atomic weight | [98] (mass number of the longest-lived isotope) |
| Molar mass | [98] g/mol |
| Category | Transition metal |
| Group | 7 |
| Period | 5 |
| Block | d-block |
| Electron configuration | [Kr] 5s2 4d5 |
| Oxidation states | +7, +6, +4 |
| Electronegativity (Pauling) | 1.9 |
| Atomic radius (van der Waals) | 209 pm |
| First ionisation energy | 7.28 eV (702.4 kJ/mol) |
| Electron affinity | 0.55 eV |
| State at room temperature | Solid |
| Melting point | 2430 K (2156.85 °C) |
| Boiling point | 4538 K (4264.85 °C) |
| Density | 11 g/cm³ |
| Discovered | 1937 |
Group 7
Calculate with Technetium
Atomic weight: IUPAC CIAAW — no standard atomic weight; mass number in brackets. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.