Mendelevium (symbol Md, atomic number 101) is a synthetic actinide named after Dmitri Mendeleev. It is classified as a actinide and sits in the actinide series (f-block), period 7 of the periodic table.
Overview
Mendelevium is the chemical element with atomic number 101 and the symbol Md. With a standard atomic weight of [258], it is a actinide. In the periodic table it occupies the actinide series (f-block) and period 7, and under standard conditions it is normally a solid. Mendelevium is a synthetic actinide named after Dmitri Mendeleev.
Atomic structure
An atom of Mendelevium has 101 protons in its nucleus and, when neutral, 101 electrons arranged in the configuration [Rn] 5f13 7s2. Mendelevium has no stable isotope; the value [258] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Mendelevium was discovered in 1955 by Lawrence Berkeley National Laboratory. It follows Fermium (Fm) and precedes Nobelium (No) in order of atomic number.
| Atomic number | 101 |
|---|---|
| Symbol | Md |
| Atomic mass | [258] |
| Category | Actinide |
| Group | — |
| Period | 7 |
| Electron configuration | [Rn] 5f13 7s2 |
| Phase at STP | Solid |
| Discovered | 1955 (Lawrence Berkeley National Laboratory) |