Mendelevium (Md)
Actinide · Radioactive · Synthetic
Mendeleevium honours Dmitri Mendeleev, father of the periodic table. It was the first element made and identified one atom at a time — just 17 atoms in the discovery experiment.
Position on the periodic table
Atomic properties
| Atomic number | 101 |
|---|---|
| Atomic mass | 258 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f13 |
| Noble gas shorthand | [Rn] 5f13 7s2 |
| Electrons per shell | 2, 8, 18, 32, 31, 8, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +3, +2 |
| Electronegativity (Pauling) | 1.3 |
| Covalent radius (approx.) | Not available |
| First ionization energy | 635 kJ/mol |
| Electron affinity | 93.9 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | Not available |
| Melting point | 826.85 °C (1100 K) |
| Boiling point | Not available |
| Appearance | Not available |
| Radioactive | Yes |
| Origin | Synthetic (lab-made) |
Electron configuration of mendelevium
Mendelevium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f13, usually shortened to [Rn] 5f13 7s2. Its electrons occupy 7 shells (2, 8, 18, 32, 31, 8, 2), placing it in period 7 of the f-block. Explore it interactively in the electron configuration calculator.
Uses of mendelevium
- Fundamental research only
Biological role: None.
Occurrence: Entirely synthetic.
History and discovery
Discovered: 1955 — Lawrence Berkeley National Laboratory. Name origin: Named after Dmitri Mendeleev.
Ghiorso, Harvey, Choppin, Thompson and Seaborg created mendelevium in 1955 from einsteinium targets.
Safety notes
Radioactive; exists only fleetingly in research labs.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Mendelevium
1. What is the chemical symbol of Mendelevium?
2. What is the atomic number of Mendelevium?
3. Which category does Mendelevium belong to?
4. What is the state of Mendelevium at room temperature?
5. Which period of the periodic table is Mendelevium in?
Mendelevium FAQs
What is the atomic number of mendelevium?
Mendelevium's atomic number is 101 — every mendelevium atom has 101 protons in its nucleus.
What is the symbol for mendelevium?
Md. Named after Dmitri Mendeleev.
Is mendelevium a metal, nonmetal, or metalloid?
Mendelevium is classified as a actinide.
What state is mendelevium at room temperature?
At about 25 °C, mendelevium is a solid. It melts at 826.85 °C.
What is mendelevium used for?
Key uses include: fundamental research only.
Related elements
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