101Md258

Mendelevium

ActinidesBlock fPeriod 7solid at 20 °C
Configuration :
[Rn] 5f¹³ 7s²
Atomic mass :
258 u
French :
Mendélévium
3D Bohr-model representation of the Mendelevium atom (symbol Md, atomic number Z=101). Electron shell configuration: 2, 8, 18, 32, 31, 8, 2 electrons.
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Bohr model · educational

Bohr model of mendelevium

Bohr model of mendelevium (Md): 101 electrons in 7 shells — 2, 8, 18, 32, 31, 8, 2

Mendelevium (Md) has 101 electrons, spread over 7 shells. The diagram places them on circles around the nucleus, from the K shell — the closest — outward.

ShellElectrons
K (n = 1)2
L (n = 2)8
M (n = 3)18
N (n = 4)32
O (n = 5)31
P (n = 6)8
Q (n = 7)2

The Bohr model is a teaching picture: electrons do not travel in circular orbits, but the number of electrons per shell is exact.

Electron configuration

Full1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹³ 7s²
Short[Rn] 5f¹³ 7s²
Valence electrons15
KLMNOPQ shells
K2
L8
M18
N32
O31
P8
Q2

Electronegativity

Pauling1.3
Allen—
Mulliken (eV)—

Atomic radii

Empirical—
Calculated—
Covalent—
Van der Waals—

Successive ionisation energies

I₁635 kJ/mol
Electron affinity—

Oxidation states

+2+3
Bold states = most common.
Warm-up

Mendelevium — do you remember?

3 questions on this page. The right answer shows every time, and nothing is asked of you to play.

No account · one minute

Period 7Block fFamily Actinides
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology