Manganèse (Mn): Bohr Model, Protons, Neutrons & Electrons
Manganèse is element number 25, a transition metal in group 7, period 4. Its atom has 25 protons, 30 neutrons and 25 electrons arranged in 4 shells: 2, 8, 13, 2.
- 25 protons
- 30 neutrons
- 25 electrons
Protons, neutrons and electrons in manganese
Le atomic number of manganese is 25, so every manganese atom has 25 protons. A neutral atom has the same number of electrons, 25. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For manganese-55, that is 55 − 25 = 30 neutrons.
How to draw the Bohr model of manganese
- Draw the nucleus and write 25 p⁺ et 30 n⁰ inside it.
- Draw the first shell and put 2 electrons on it (the first shell holds at most 2).
- Draw the second shell and put 8 electrons on it.
- Draw the third shell and put 13 electrons on it.
- Draw the fourth shell and put 2 electrons on it.
- Check: 2 + 8 + 13 + 2 = 25 electrons, the same as the number of protons.
From potassium onwards the shells don’t simply fill as 2, 8, 8: the fourth shell starts before the third is full, so the real arrangement above (2, 8, 13, 2) is the one to draw.
Electron configuration
The electron configuration of manganese is [Ar] 4s² 3d⁵. As a transition metal it fills an inner d-subshell, and its common ion is Mn²⁺.
Key facts about manganese
| Symbol | Mn |
|---|---|
| Atomic number | 25 |
| Relative atomic mass | 54.938 |
| Group · period · block | group 7 · period 4 · d-block |
| Type | Métal de transition |
| State at 25 °C | solid |
| Couches électroniques | 2, 8, 13, 2 |
| Electron configuration | [Ar] 4s² 3d⁵ |
| Électrons de valence | varies (outer shell: 2) |
| Common ion | Mn²⁺ |
| Electronegativity (Pauling) | 1.55 |
| First ionisation energy | 7.43 eV (717 kJ/mol) |
| Atomic radius (empirical) | 140 pm |
Où manganese sits on the periodic table
Foire aux questions
How many protons, neutrons and electrons does manganese have?
Manganese has 25 protons and 25 electrons (atomic number 25). Its most common isotope, manganese-55, has 55 − 25 = 30 neutrons.
What is the electron configuration of manganese?
[Ar] 4s² 3d⁵. In shells that is 2, 8, 13, 2.
How many valence electrons does manganese have?
Manganese is a transition metal, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is manganese on the periodic table?
In group 7, period 4, in the d-block. It is a transition metal.
