Technetium
Definition and meaning of Technetium in chemistry.
![Technetium element card: symbol Tc, atomic number 43, atomic mass [98], electron configuration [Kr] 4d⁵ 5s², oxidation states +7 +4, Transition metal, group 7, period 5, solid at room temperature.](/assets/images/terms/technetium-chemical-element.webp)
Technetium is a silvery-gray, radioactive transition metal with the symbol Tc and atomic number 43. It is the lightest element in the periodic table that has no stable isotopes. All forms of this element are radioactive and break down over time.
In more detail
Technetium sits in group 7 of the periodic table, between manganese and rhenium. Because it has an odd atomic number, it lacks stable nuclear configurations. Scientists must produce technetium artificially in nuclear reactors by splitting uranium atoms.
The most stable isotope is technetium-98, which has a half-life of 4.2 million years. Since the Earth is billions of years old, any original technetium decayed away long ago. This explains why the element is virtually nonexistent in nature today.
Chemically, technetium behaves like manganese and rhenium, showing common oxidation states of +4 and +7. The pure metal tarnishes slowly in moist air to form oxides. It dissolves in oxidizing acids like nitric acid but resists hydrochloric acid.
Students often wonder if technetium behaves like a typical metal in experiments. Yes, it conducts electricity and heat just like other transition metals on the periodic table. It also becomes a superconductor when it is cooled to very low temperatures.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Tc |
| Atomic number | 43 |
| Atomic mass | [98] u |
| Category | Transition-Metal |
| State at room temperature | Solid |
| Year discovered | 1937 |
Doctors use the isotope technetium-99m as a radioactive tracer in medical imaging. The lowercase 'm' means it is in a temporary, high-energy state. Doctors inject this tracer into a patient's body to highlight bones and internal organs. The tracer releases gamma rays that special medical cameras can detect easily. This process works well because the isotope has a short half-life of six hours. This short half-life ensures the patient receives a very low radiation dose. Once the test is complete, the chemical quickly decays into a safer element.
Frequently asked questions
Can technetium be found naturally on Earth?
Only trace amounts exist naturally in uranium ores from spontaneous fission. Almost all technetium on Earth is created synthetically in reactors.
Why was technetium so difficult to discover?
It has no stable isotopes, so it decayed away over Earth's history. Scientists had to synthesize it using particle accelerators to confirm its existence.
How does technetium leave the human body after a scan?
The tracer decays quickly due to its six-hour half-life. The body also filters out the remaining chemical through normal waste processes.
Related terms
Sources & references
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