QUICK REFERENCE
- Symbol: Md
- Atomic Number: 101
- Atomic Weight: [258]
- Element Classification: Actinide
- Discovered By: Albert Ghiorso, Glenn T. Seaborg, Bernard G. Harvey, Gregory R. Choppin, and Stanley G. Thompson
- Discovery Date: 1955
- Name Origin: Named after Dmitri Mendeleev, the creator of the periodic table
- Density(g/cc): Not well determined; estimated around 10.3 (predicted)
- Melting Point: 827°C (estimated)
- Boiling Point: Not determined
- Appearance: Presumed to be a metallic solid under normal conditions, but its actual appearance is unknown due to its radioactivity and production in only microscopic amounts
- Atomic Radius(pm): Estimated
Discovery
Mendelevium was discovered in 1955 by a team led by Albert Ghiorso, Glenn T. Seaborg, Bernard G. Harvey, Gregory R. Choppin, and Stanley G. Thompson at the Lawrence Berkeley National Laboratory. The element was synthesized by bombarding einsteinium-253 with alpha particles (helium nuclei) using the Berkeley cyclotron. This made mendelevium the first element to be synthesized one atom at a time. The element was named in honor of Dmitri Mendeleev, the Russian chemist who is credited with creating the periodic table, recognizing his contributions to the field of chemistry.
Relation to Other Elements
Mendelevium is a member of the actinide series and shares common properties with other actinides, such as being radioactive and having multiple potential oxidation states. The most common oxidation state for mendelevium in aqueous solutions is +2, which is somewhat unusual among the later actinides that typically exhibit a +3 oxidation state. Due to its position in the periodic table, mendelevium’s chemical properties have been studied only to a limited extent through experiments involving very small amounts of the element.
Natural Occurrence
Mendelevium does not occur naturally on Earth and is produced synthetically in particle accelerators through the bombardment of lighter actinide targets with charged particles.
Uses
The applications of mendelevium are confined almost exclusively to scientific research due to its short half-life, the difficulty of producing it, and its intense radioactivity:
- Scientific Research: Mendelevium’s use is primarily in basic scientific studies aimed at understanding the properties of actinide elements. Research involving mendelevium includes investigations into its chemical behavior, nuclear structure, and potential oxidation states.
- Synthesis of Heavier Elements: Similar to other heavy actinides, mendelevium has been used as a target material in particle accelerators for the synthesis of heavier elements, further expanding our understanding of the periodic table and the limits of element stability.
The discovery of mendelevium was a significant achievement in nuclear chemistry, demonstrating the ability to create and identify new elements atom by atom. While it has no practical applications outside of research, mendelevium has played a crucial role in the study of transuranium elements and the exploration of the periodic table’s outermost reaches.