43Tc98.000
Transition Metald-blockRadioactive
Technetium
Element 43 on the periodic table, symbol Tc, group 7, period 5.
Technetium (/tɛkˈniːʃiəm/) is a chemical element with symbol Tc and atomic number 43. It is the element with the lowest atomic number in the periodic table that has no stable isotopes: every form of it is radioactive. Nearly all technetium is produced synthetically, and only minute amounts are found in nature.
Appearance: shiny gray metal
Properties
- Atomic Number
- 43
- Atomic Mass
- 98.0000 u
- Group
- 7
- Period
- 5
- Block
- d-block
- Category
- Transition Metal
- State at 25 °C
- Solid
- Melting Point
- 2,430 K · 2,156.9 °C
- Boiling Point
- 4,538 K · 4,264.9 °C
- Density
- 11 g/cm³
- Atomic Radius
- 135 pm
- Electronegativity
- 1.9
- Oxidation States
- +4, +7
- Abundance in Crust
- Vanishingly rare
- Discovered
- 1937
- Discovered By
- Emilio Segrè
Electron Configuration
[Kr] 4d5 5s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d5
Ionisation Energies (kJ/mol)
- 1. 702
- 2. 1,470
- 3. 2,850
Elements near Technetium
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.