Element 43
Technetium
Transition metals
Technetium (Tc) is in the d-block of the periodic table — group 7, period 5.
Technetium (/tɛkˈniːʃiəm/) is a chemical element with symbol Tc and atomic number 43.
Key data
- Atomic number
- 43
- Atomic mass
- 98.000 u
- Group / Period
- 7 / 5
- Block
- d-block
- Phase at STP
- Solid
- Density
- 11 g/cm³
- Melting point
- 2156.8 °C
- Boiling point
- 4264.9 °C
- Electron configuration
- [Kr] 4d5 5s2
Periodic table block
Technetium is in the d-block (group 7, period 5). Elements land in the d-block when their highest-energy electrons fill a d subshell — these are the transition metals in the middle of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Medical imaging
- •Steel additive (rare)
- •First synthetic element
Discovery
Year: 1937
Discovered by: Emilio Segrè
Frequently asked questions
What is the atomic number of Technetium?
Technetium has atomic number 43. Its symbol is Tc and its atomic mass is 98 u.
What category of element is Technetium?
Technetium is classified as transition metals. It sits in group 7, period 5 of the periodic table.
What block of the periodic table is Technetium in?
Technetium is in the d-block (group 7, period 5). Its highest-energy electrons occupy the d subshell — you can see this in its electron configuration, [Kr] 4d5 5s2.
What is Technetium used for?
Common uses of Technetium include: Medical imaging, Steel additive (rare), First synthetic element.
When was Technetium discovered?
Technetium was discovered in 1937 by Emilio Segrè.
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