Radium is a chemical element with an atomic number of 88 and is represented by the symbol ‘Ra’ in the periodic table. It is silvery-white in appearance classified as alkaline earth metal and belongs to group 2 of the periodic table. Because of its high radioactivity and rarity, radium is often only accessible as compounds, notably radium chloride or radium bromide.
Radium is a soft, shiny, silvery-white metal that is extremely radioactive. Radium is approximately 2.7 million times more radioactive compared to uranium. It is created when uranium and thorium radioactively decay in the environment. Radium is derived from pitchblende, a uranium-rich mineral, and ore (UO2).
History of Radium
- Marie S. Curie and her husband Pierre discovered radium in pitchblende (primarily uranium dioxide, UO2) in 1898 in Paris.
- This was Curie’s second important discovery in 1898; earlier that year, they found polonium, a new radioactive element with characteristics comparable to bismuth.
- Additionally, metallic radium was obtained in 1910 by Marie Curie and Andrew Debierne by electrolysis of radium chloride (RaCl2), the first purified radium compound.
- The element’s name is derived from the Latin word ‘radius,’ which means ray, and refers to the rays released by this radioactive element.
Occurrence of Radium
- The crust of the Earth contains extremely little radium. An estimate of its abundance places it at 0.0000001 parts per million.
- It is found not just in pitchblende, but in all uranium-containing ores. It is produced when uranium emits radiation and degrades.
- Seawater contains extremely trace amounts of radium. The abundant 238U decays to produce the majority of radium, 226Ra. Therefore, uranium manufacturing waste is used to produce radium.
- Radium is obtained via a process similar to the Curies’. The metal is dissociated from the other elements of pitchblende by a drawn-out series of chemical reactions.
Isotopes of Radium
- Radium has four naturally occurring isotopes: 223Ra, 224Ra, 226Ra, and 228Ra.
- Only 226Ra is commercially useful. Its half-life is 1,620 years. After that time, just half of the original sample would be left.
- 226Ra, the only isotope that is being utilized often, is typically not employed directly. Instead, radon (Rn) gas is produced using it. One of the byproducts of the breakdown of radium is radon gas.
Elemental Properties of Radium
|Electronic Configuration||[Rn] 7s2|
|Atomic Weight||(226) no stable isotope|
|State at 20°C||Solid|
|Group, Period, and Block||2, 7, s-block|
|Density||5.5 g.cm -3 at 20 °C|
|Van der Waals radius||0.230 nm|
|Electron shells||2, 8, 18, 32, 18, 8, 2|
|Neutrons in the most abundant isotope||138|
Physical Properties of Radium
Radium has an atomic number of 88 and is a silvery-white alkaline earth metal. It has a melting point of 700 °C (1292 °F) and a boiling point of 1737 °C (3159 °F).
Radium has a solid phase density of 5.5 g/cm3 at room temperature.
Radium has a body-centered cubic structure at STP.
|Color/physical appearance||metallic, silvery-white|
|Melting point/freezing point||973 K (700 °C, 1292 °F)|
|Boiling point||2010 K (1737 °C, 3159 °F)|
|Density||5.5 g cm-3 at 20°|
Chemical Properties of Radium
- Radium is a very reactive metal.
- Most nonmetals, including oxygen(O), fluorine(F), chlorine, and nitrogen, mix with radium.
- When exposed to air, it immediately combines with nitrogen to generate a black covering of radium nitride.
- It may also react with acids to produce hydrogen gas.
- Radium compounds have an oxidation state of +2 at all times.
- Radium is a highly reactive metal that always shows its group oxidation state. It generates the colorless Ra2+ cation in an aqueous solution, which is very basic and does not form complexes.
- The majority of radium compounds are simple ionic compounds.
Chemical Reaction of Radium
- The Reaction of Radium with Air
When radium metal burns in the air, it produces a combination of white radium oxide, RaO, and radium nitride, Ra3N2. In this process, the superoxide RaO2 is also likely to appear.
2 Ra (s) + O2 (g) → 2 RaO (s)
Ra (s) + O2 (g) → RaO2 (s)
3 Ra (s) + N2 (g) → Ra3N2 (s)
- The Reaction of Radium with Water
Radium most likely combines quickly with water to generate radium hydroxide, Ba(OH)2, and hydrogen gas (H2). The reaction is projected to be faster than that of barium.
Ra (s) + 2H2O (g) → Ra(OH)2 (aq) + H2 (g)
Uses of Radium
Given its high radioactivity, radium has limited uses nowadays. Some of the uses are mentioned here:
- 223Ra is used to treat prostate cancer that has progressed to the bones on occasion. Because bones contain calcium and radium belongs to the same element family as calcium, it can be utilized to target malignant bone cells. It emits alpha particles, which can destroy malignant cells.
- Radium was once utilized in illuminating paints, such as clocks and watch dials. Although alpha radiation could not travel through the glass or metal of the watch case, it is currently thought that it might be too risky to employ in this manner.
- 226Ra, the only isotope that is being utilized often, is typically not employed directly. Instead, radon gas is produced using it. One of the byproducts of the breakdown of radium is radon gas.
Health Effect of Radium
- Radium, like all radioactive elements, is a hazardous substance to handle. The radiation it emits has the potential to harm live cells.
- This characteristic is advantageous in the treatment of cancer. Cancer cells can be killed to aid a patient’s recovery.
- However, while utilizing radium for this specific purpose, extreme caution must be exercised. Its radiation has the potential to destroy healthy cells as well.
- Radium workers must use extreme caution to avoid getting the element on their skin, swallowing it, or inhaling its fumes.
- There is no evidence that naturally occurring quantities of radium are hazardous to human health.
- Higher amounts of radium exposure, on the other hand, may cause health problems such as tooth breakage, anemia, and cataracts.
- Marie Curie died as a result of her work with radium. She was diagnosed with leukemia and died in 1934.
Environmental Effects of Radon
- Radium is continually created by the radioactive decay of uranium and thorium. Radium is found at extremely low levels in rocks and soil and firmly binds to them. It can also be found in the air. Radium concentrations in water are high in some places.
- Radium levels in water around uranium mines increase as a result of mining. Radium is absorbed by plants from the soil. Radium will build up in animals that eat these plants.
- Finally, radium may accumulate in fish and other aquatic species and biomagnify its way up the food chain.