Promethium atomic number isotopes properties and uses in nuclear chemistry
The Promethium element is represented by the symbol Pm. Promethium is a lanthanide and a rare earth metal. All the isotopes of promethium are radioactive in nature. Promethium metal emits beta radiation. As it is a rare metal, so its chemical and physical characteristics are not well known. Promethium salts have a pink or red colour that gives a pale blue-green glow to the ambient air. Promethium metal was discovered by Mariinsky in 1945.
Electronic configuration- [Xe]4f56s2
The atomic number of promethium- 61
The atomic mass of promethium- 145gmol-1
Physical Properties of Promethium
Promethium is the f-block element that belongs to the group lanthanides and period 6. It is solid at 20°C.
Melting point- 1042°C, 1908°F, 1315 K
Boiling point- 3000°C, 5432°F, 3273 K
The density of promethium- 7.26
Chemical Properties of Promethium
Chemically, promethium is a lanthanide, when mixed with other elements, forms salts. It shows only one stable state of oxidation of +3.
Since traces of the element are extremely scarce in nature, the element is typically synthesized to produce promethium-147 by bombarding enriched uranium with thermal neutrons.
Promethium salts have pink or red colour with a pale blue-green light that colours the surrounding air.
Promethium Uses
Most promethium is used only for research purposes except for promethium-147, which can be found outside laboratories. It is obtained in milligram quantities as oxide or chloride. This isotope does not emit gamma rays, and its radiation has a relatively small depth of penetration in the matter and a relatively long half-life.
Promethium used as a pacemaker. A luminous paint containing a phosphor that absorbs the beta radiation emitted by promethium-147 and emits light is used by some signal lights.
In atomic batteries, by sandwiching a small promethium source between two semiconductor plates, the beta particles emitted by promethium-147 are converted into electric current. These batteries have a lifetime of approximately five years. Promethium is often used to measure the thickness of materials by measuring the amount of radiation from a promethium source that passes through the sample. Potential applications can be made for portable X-ray sources and as auxiliary heat or power sources for space probes and satellites.
Precautions
The promethium does not have a biological function. During its beta decay, Promethium-147 will emit gamma rays that are harmful to all life forms. encounters with small amounts of promethium-147 are not dangerous If certain precautions are taken. In general, gloves, footwear covers, safety glasses, and an outer layer of protective clothing that can be quickly removed should be used.
Promethium mainly affects bone tissue. It is not risky to have a sealed promethium-147. If the packaging is impaired, however, then promethium becomes harmful for the environment and humans. The polluted area should be cleaned with water and soap if radioactive contamination is detected.
Did You Know?
There in the Andromeda galaxy is the peculiar star HR 465, which contains a lot of Promethium. It is very radioactive and rare, very little has been studied: it is not well described in its chemical and physical properties.
FAQs on Promethium Element Overview and Chemical Properties
1. What is promethium?
Promethium is a radioactive chemical element with atomic number 61 and symbol Pm, belonging to the lanthanide series of the periodic table.
- It is a rare earth element located in Period 6, f-block.
- All its isotopes are radioactive; it has no stable isotopes.
- It is a silvery metal that slowly oxidizes in air.
- The most common isotope is Pm-147, used in nuclear batteries.
2. What is the atomic number and electronic configuration of promethium?
The atomic number of promethium is 61, and its ground-state electronic configuration is [Xe] 4f5 6s2.
- It belongs to the lanthanides (4f block).
- The valence electrons are mainly in the 4f and 6s orbitals.
- This configuration explains its typical +3 oxidation state.
3. Why is promethium radioactive?
Promethium is radioactive because all of its isotopes have unstable nuclei that undergo radioactive decay.
- It has no stable combination of protons and neutrons.
- Common isotope Pm-147 undergoes beta (β-) decay.
- Its half-life is about 2.62 years, leading to gradual nuclear transformation.
4. Where is promethium found in nature?
Promethium is found in nature only in trace amounts in uranium ores as a product of nuclear fission.
- It forms during the spontaneous fission of U-238.
- Because of its short half-life, it does not accumulate naturally.
- Most promethium is synthetically produced in nuclear reactors.
5. How is promethium produced?
Promethium is produced artificially by nuclear fission of uranium in nuclear reactors.
- It is obtained as a fission product when U-235 absorbs a neutron and splits.
- Example (simplified): 235U + n → fission fragments + Pm isotopes + neutrons.
- The desired isotope (usually Pm-147) is separated chemically from other fission products.
6. What are the common oxidation states of promethium?
The most common oxidation state of promethium is +3.
- In aqueous solution, it forms the ion Pm3+.
- This is typical of lanthanide elements.
- Compounds such as PmCl3 and Pm2O3 contain promethium in the +3 state.
7. What are the physical properties of promethium?
Promethium is a silvery, soft, radioactive metal with properties similar to other lanthanides.
- Atomic mass (Pm-145): approximately 145 u.
- Melting point: about 1042 °C.
- It tarnishes slowly in air due to oxidation.
- It is paramagnetic because of its unpaired 4f electrons.
8. What are the uses of promethium?
Promethium is mainly used in nuclear batteries and luminous devices due to its beta radiation.
- Pm-147 is used in radioisotope thermoelectric generators.
- It has been used in self-luminous paint for watches and instruments.
- It serves as a portable X-ray source in research applications.
9. What are some important compounds of promethium?
Important promethium compounds include PmCl3, Pm2O3, and Pm(NO3)3.
- PmCl3 (promethium(III) chloride) is a common halide.
- Pm2O3 is its typical oxide in the +3 state.
- Most compounds contain the Pm3+ ion.
10. Is promethium dangerous or toxic?
Promethium is considered hazardous mainly because it is radioactive, not due to high chemical toxicity.
- It emits beta radiation (β-).
- Exposure can damage biological tissues due to ionizing radiation.
- Strict handling and shielding procedures are required in laboratories.
