#25 / 118
25Mn54.938
Transition Metalssolid at STPD-block

Manganese

Group: 7Period: 4Standard Atomic Weight: 54.938 u

Why is Manganese in this position?

Understanding the scientific rationale behind Manganese's position in the periodic table:

Group Assignment
Group 7

Belongs to Group 7 because it has 7 valence electrons (3d⁵ 4s²).

Period Assignment
Period 4

Belongs to Period 4 because its outermost electrons occupy n=4.

Orbital Block
D-block

Belongs to the d-block because its valence subshell is 3d.

Chemical Category
Transition Metals

Classified as a transition metal, possessing the widest range of common oxidation states (+2 to +7) in Period 4.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 13, 2]

Bohr Atomic Shell Model(2, 8, 13, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

25 Protons (p⁺)30 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 13Shell M: Electron 2 of 13Shell M: Electron 3 of 13Shell M: Electron 4 of 13Shell M: Electron 5 of 13Shell M: Electron 6 of 13Shell M: Electron 7 of 13Shell M: Electron 8 of 13Shell M: Electron 9 of 13Shell M: Electron 10 of 13Shell M: Electron 11 of 13Shell M: Electron 12 of 13Shell M: Electron 13 of 13NShell N: Electron 1 of 2Shell N: Electron 2 of 2MnZ = 25

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):13 / 18 electrons (72%)
Shell N (n=4):2 / 32 electrons (6%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²

Neutral ground state configuration. Valence electrons: 7.

Atomic & Quantum Properties

Electronegativity (Pauling)1.55 Pauling
1st Ionization Energy717.3 kJ/mol
Electron Affinity0 kJ/mol
Atomic Radius (empirical)161 pm
Common Oxidation States+2, +4, +7
Crystal StructureCubic (complex)

Physical & Thermal Properties

Density at STP7.21 g/cm³
Melting Point1246 °C (1519 K)
Boiling Point2061 °C (2334 K)
Magnetic OrderingParamagnetic
Discovery Year1774
Discovered ByJohan Gottlieb Gahn

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Steelmaking alloying element to increase work-hardening strength and toughness (Hadfield steel)
  • Cathode material in lithium-ion and alkaline batteries (MnO₂ / LiMn₂O₄)
  • Potassium permanganate (KMnO₄) powerful laboratory and municipal water disinfectant
  • Fertilizer micronutrient and animal feed dietary supplement
Occurrence in Nature

Abundant in minerals like pyrolusite (MnO₂), rhodochrosite, and vast polymetallic manganese nodules on the deep ocean floor.

Etymology & Name Origin

From Latin 'magnes' meaning magnet, historically confused with magnetic iron ores

Important Chemical Compounds
MnO₂ (Manganese dioxide)
KMnO₄ (Potassium permanganate)
MnSO₄ (Manganese sulfate)
Mn₂O₇ (Manganese heptoxide)
Interesting Chemical Facts
  • Hadfield manganese steel (12% Mn) becomes significantly harder when struck or deformed, making it perfect for railway switches and bulldozer blades.
  • The Oxygen-Evolving Complex (OEC) in photosystem II contains a catalytic cluster of 4 manganese atoms that split water molecules during photosynthesis.
  • Potassium permanganate is such a vivid purple dye that a single crystal will color an entire beaker of water.
Safety & Handling Note

Chronic occupational inhalation of manganese dust causes Manganism, a debilitating neurological disorder resembling Parkinson's disease.