Elements

Electron configuration of Manganese (Mn)

Read the Manganese electron configuration, noble-gas shorthand, valence shell, orbital filling logic, and the mistakes to avoid when writing Mn.

Guide: Guía práctica Read: 5 min Updated: 2026-06-21

Element guide

Electron configuration of Manganese (Mn)

The electron configuration of Manganese is 1s2 2s2 2p6 3s2 3p6 3d5 4s2. In shorthand form it is written as [Ar] 3d5 4s2.

Use this page to connect the notation with atomic number 25, the d-block, and the valence pattern 4s2.

How to write the configuration

Configuration at a glance

Manganese has atomic number 25, so a neutral atom has 25 electrons. The configuration 1s2 2s2 2p6 3s2 3p6 3d5 4s2 is a compact record of where those electrons sit by subshell. The number before each letter is the principal energy level, the letter names the subshell, and the superscript tells you how many electrons are assigned there.

The shorthand [Ar] 3d5 4s2 replaces the filled inner core with the previous noble gas. That notation keeps attention on the electrons that usually explain bonding, ions, and periodic trends.

Manganese follows the standard filling order

Manganese is a period 4 transition metal that follows the standard Aufbau sequence: 1s2 2s2 2p6 3s2 3p6 4s2 3d5. Note that 4s fills before 3d, but when manganese forms ions, the 4s electrons are lost first.

Step-by-step filling walkthrough: 1. Start with atomic number 25. 2. Follow the Aufbau sequence: fill 1s, 2s, 2p, 3s, 3p, then continue through 4s, 3d, 4p in order. 3. Keep a running total of electrons after each subshell. 4. Write the noble-gas shorthand by replacing the filled core with the previous noble gas in brackets. 5. Verify: add every superscript and confirm the total equals 25.

Half-filled d-subshell stability

Manganese has a half-filled 3d5 subshell, which gives it extra stability compared to elements with 3d4 or 3d6 configurations. This half-filled shell is why Mn2+ ions are relatively common: losing two 4s electrons leaves [Ar] 3d5, which is electronically stable. Manganese also shows a wide range of oxidation states from +2 to +7, with Mn2+ (3d5), Mn4+ (3d3), and Mn7+ (3d0) being particularly important in chemistry.

Real-world applications

  • MnO2 (manganese dioxide) is used in dry-cell batteries as a cathode material.
  • KMnO4 (potassium permanganate) is a strong oxidizing agent used in water treatment and organic synthesis.
  • Manganese is an essential trace element in human nutrition, required for bone formation and enzyme function.
  • Steel production uses manganese to improve strength and remove impurities.

Common ions: Mn2+ ([Ar] 3d5), Mn4+ ([Ar] 3d3), Mn7+ ([Ar]).

Manganese reference table

Item Value
Atomic number 25
Full configuration 1s2 2s2 2p6 3s2 3p6 3d5 4s2
Noble-gas notation [Ar] 3d5 4s2
Valence clue 4s2
Block d-block

Use the table as a learning reference, then verify advanced oxidation-state questions with your course material.

Before you submit an answer

  • The superscripts add up to 25 for a neutral Manganese atom.
  • The notation follows the filling order used in your course.
  • The last occupied subshell matches the periodic-table block.
  • Any transition-metal or actinide exception is checked against a reference.
  • The shorthand core is a noble gas, not a random previous element.

Common questions

What is the electron configuration of Manganese?

The neutral Manganese atom is written as 1s2 2s2 2p6 3s2 3p6 3d5 4s2. The shorthand form is [Ar] 3d5 4s2.

How many valence electrons does Manganese have?

Start from the outer-shell clue 4s2. For transition metals, inspect both s and d electrons carefully since both can participate in bonding.

Why does Mn2+ have a half-filled d-subshell?

Mn2+ loses the two 4s electrons, leaving [Ar] 3d5. A half-filled d-subshell (five electrons with one in each orbital) is energetically favourable due to exchange energy and minimal electron-electron repulsion.

What are the common oxidation states of Manganese?

Mn2+ (3d5) and Mn7+ (3d0) are the most stable in aqueous chemistry, but Mn4+ (3d3) in MnO2 and Mn6+ (3d1) in manganates are also well-known.

Study notes and practice checks

Element-specific practice problems

Problem 1: Write the full electron configuration for neutral Manganese and verify the electron count against 25.

Problem 2: Convert the full configuration to noble-gas shorthand notation.

Problem 3: Predict the electron configurations of Mn2+, Mn4+, and Mn7+. Which one has the most stable d-subshell configuration?

Problem 4: Compare the configuration of Manganese (Z=25) with Chromium (Z=24) and Iron (Z=26). Why does Chromium have an exceptional 4s1 3d5 configuration while Manganese follows the standard pattern?

Problem 5: How does the half-filled d-subshell affect manganese's chemical reactivity compared to its neighbours?

Elena Marquez

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Elena Marquez

Chemistry educator and study-guide editor

Elena explains electron configurations, orbital diagrams, and periodic trends for learners who need clear steps before memorization. Her guides focus on counting, notation, and common classroom mistakes.

Credenciales: Editorial specialization in introductory chemistry, periodic trends, and student reference material.

Experiencia: More than eight years preparing practical chemistry explainers, worksheets, and reference material for independent learners.

Actualizado: 2026-06-21 Politica editorial Correcciones

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