Chemical element · Atomic number 43
Technetium
Technetium in the periodic table: atomic number 43, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Transition metal
solid
[96.90636] u
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Atomic classification
Shell occupancy
Technetium in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 18 electrons
- N · n=4
- 13 electrons
- O · n=5
- 2 electrons
- Electron configuration
- [Kr]5s2 4d5
- Electrons per shell
- 2 · 8 · 18 · 13 · 2
- Group
- 7
- Period
- 5
- Block
- D
- Element category
- Transition metal
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Physical and chemical properties
- Atomic mass
- [96.90636] u
- Standard state
- solid
- Density
- 11 g/cm³
- Melting point
- 2,430 K
- Boiling point
- 4,538 K
- Electronegativity
- 1.9 (Pauling)
- First ionisation energy
- 7.28 eV
- Oxidation states
- +7, +6, +4
- Discovery
- 1937
Safety and periodic classification
Safety
Safe handling cannot be inferred from Technetium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Technetium is in period 5, group 7 and the D block. Its direct neighbours by atomic number are Molybdenum and Ruthenium. The recorded Pauling electronegativity is 1.9. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.