Mendelevium (Md)
Mendelevium is element 101, a actinide in period 7 of the periodic table. At room temperature it is of unknown state (too few atoms have ever been made).
Electron configuration [Rn] 5f13 7s2
Electrons per shell 2, 8, 18, 32, 31, 8, 2
Mendelevium data
| Atomic number | 101 |
|---|---|
| Symbol | Md |
| Atomic mass | [258] (mass number of the longest-lived isotope) |
| Category | Actinide |
| Group | — (f-block) |
| Period | 7 |
| Block | f |
| State at 25 °C | unknown |
| Melting point | 1100 K (826.9 °C) |
| Boiling point | — |
| Density | — |
| Electronegativity (Pauling) | 1.3 |
| Atomic radius | — |
| 1st ionization energy | 635 kJ/mol |
| Electron affinity | — |
| Oxidation states | +2, +3 |
| Common ion charge | 3+ |
| Discovered | 1955 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through mendelevium’s configuration and its ions →
Where mendelevium sits
Mendelevium belongs to the actinides. Its Pauling electronegativity of 1.3 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Mendelevium FAQ
What is the electron configuration of mendelevium?
Mendelevium (Z = 101) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f13 7s2. In noble-gas shorthand that is [Rn] 5f13 7s2.
How many valence electrons does mendelevium have?
2 (2 in the outer s subshell).
What is the atomic mass of mendelevium?
Mendelevium has no stable isotopes. Its most stable known isotope has mass number 258, so tables list [258].
Is mendelevium a metal?
Yes. Mendelevium is a actinide.
What is the charge of a mendelevium ion?
Mendelevium most commonly forms Md3+.