The atomic number of Mn (Manganese) is 25. Manganese is a transition metal in Group 7 (VIIB), Period 4 of the periodic table. Its atomic mass is approximately 55 u (54.938 u). The electronic configuration of manganese is [Ar] 3d⁵ 4s² or 2, 8, 13, 2. Manganese is notable for having a half-filled 3d subshell (3d⁵) in its ground state, giving it extra stability.
Atomic number of Mn (Manganese) = 25.
Atomic mass of Mn = 55 u (54.938 u).
Electronic configuration: [Ar] 3d⁵ 4s² = 2, 8, 13, 2.
Group 7 (VIIB), Period 4, d-block (transition metal).
3d⁵ = half-filled subshell → extra stable configuration.
Oxidation states: +2 to +7 (widest range among transition metals).
KMnO₄ (Mn = +7): strong oxidising agent, purple colour.
MnO₂ (Mn = +4): used in dry cell batteries as depolariser.
Mn-55 is the only naturally occurring stable isotope of manganese.
Symbol: Mn Atomic Number: 25 Atomic Mass: 55 u (precisely 54.938 u) Group: 7 (Group VIIB) Period: 4 Block: d-block (transition metal) Electronic Configuration: [Ar] 3d⁵ 4s² = 2, 8, 13, 2 Physical state: Solid (hard, grey-white metal)
Number of subatomic particles in Mn-55 (most common isotope): • Protons: 25 • Neutrons: 55 − 25 = 30 • Electrons: 25 (neutral atom)
Oxidation states of Manganese: Mn is unique in showing the widest range of oxidation states (+2 to +7) among transition metals: • +2: MnO, MnSO₄, MnCl₂ (most stable) • +4: MnO₂ (manganese dioxide — most common oxide) • +6: MnO₄²⁻ (manganate ion, green colour) • +7: KMnO₄ (potassium permanganate — intense violet/purple colour)
Full electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²
Shortened form: [Ar] 3d⁵ 4s²
Shell-wise: 2, 8, 13, 2
Why 3d⁵ is special: • 3d⁵ is a half-filled d subshell • Half-filled and completely filled subshells are extra stable (Hund's rule) • Each 3d orbital has exactly 1 electron → maximum spin multiplicity • This makes Mn unique among transition metals
For Mn²⁺ ion: • Mn loses 2 electrons (from 4s² first) • Mn²⁺ config: [Ar] 3d⁵ (5 unpaired electrons) • This configuration has maximum paramagnetism
For Mn⁷⁺ (in KMnO₄): • Mn loses 7 electrons • Mn⁷⁺ config: [Ar] (empty d shell) • High oxidation state → strong oxidising agent
Key Manganese Compounds:
Potassium Permanganate (KMnO₄) • Mn oxidation state: +7 • Intense purple/violet colour in solution • Strong oxidising agent • Used in volumetric analysis (permanganometry) • Used as disinfectant, water purification
Manganese Dioxide (MnO₂) • Mn oxidation state: +4 • Black/brown solid • Used in dry cells (Leclanché cell) as depolariser • Used as oxidising agent in lab
Manganous Sulphate (MnSO₄) • Mn oxidation state: +2 • Used as fertiliser and in animal feed
Uses of Manganese: • Steel production: Mn is added to steel to improve hardness and strength (Ferromanganese alloy) • Dry cell batteries (as MnO₂) • Pigments and dyes • Essential trace element for plants and animals • Mn is required for photosynthesis — part of the oxygen-evolving complex in Photosystem II
The atomic number of Mn (Manganese) is 25. It is a transition metal in Group 7, Period 4 of the periodic table. Atomic mass = 55 u. Electronic configuration: [Ar] 3d⁵ 4s² (or 2, 8, 13, 2).
Electronic configuration of Mn: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s², shortened as [Ar] 3d⁵ 4s². Shell-wise: 2, 8, 13, 2. The 3d⁵ (half-filled d subshell) gives manganese extra stability.
Manganese shows the widest range of oxidation states among transition metals: +2 (most stable, e.g., MnSO₄), +4 (e.g., MnO₂ in dry cells), +6 (manganate MnO₄²⁻, green), and +7 (permanganate KMnO₄, purple — strongest oxidising state). Mn can also show +1, +3 in some compounds.
Manganese-55 (the only stable isotope): neutrons = 55 − 25 = 30. Mn is monoisotopic (only one naturally occurring stable isotope: Mn-55), so all natural Mn atoms have 30 neutrons.
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