Osmium (Os): Bohr Model, Protons, Neutrons & Electrons
Osmium is element number 76, a transition metal in group 8, period 6. Its atom has 76 protons, 116 neutrons and 76 electrons arranged in 6 shells: 2, 8, 18, 32, 14, 2.
- 76 protons
- 116 neutrons
- 76 electrons
Protons, neutrons and electrons in osmium
Le atomic number of osmium is 76, so every osmium atom has 76 protons. A neutral atom has the same number of electrons, 76. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For osmium-192, that is 192 − 76 = 116 neutrons. Osmium has 7 stable isotopes, with 108, 110, 111, 112, 113, 114, 116 neutrons.
How to draw the Bohr model of osmium
- Draw the nucleus and write 76 p⁺ et 116 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 18 electrons on it.
- Draw the fourth shell and put 32 electrons on it.
- Draw the fifth shell and put 14 electrons on it.
- Draw the sixth shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 14 + 2 = 76 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, 18, 32, 14, 2) is the one to draw.
Electron configuration
The electron configuration of osmium is [Xe] 6s² 4f¹⁴ 5d⁶. As a transition metal it fills an inner d-subshell, and its common ion is Os⁴⁺.
Key facts about osmium
| Symbol | Os |
|---|---|
| Atomic number | 76 |
| Relative atomic mass | 190.23 |
| Group · period · block | group 8 · period 6 · d-block |
| Type | Métal de transition |
| State at 25 °C | solid |
| Couches électroniques | 2, 8, 18, 32, 14, 2 |
| Electron configuration | [Xe] 6s² 4f¹⁴ 5d⁶ |
| Électrons de valence | varies (outer shell: 2) |
| Common ion | Os⁴⁺ |
| Electronegativity (Pauling) | 2.20 |
| First ionisation energy | 8.44 eV (814 kJ/mol) |
| Atomic radius (empirical) | 130 pm |
Où osmium sits on the periodic table
Foire aux questions
How many protons, neutrons and electrons does osmium have?
Osmium has 76 protons and 76 electrons (atomic number 76). Its most common isotope, osmium-192, has 192 − 76 = 116 neutrons.
What is the electron configuration of osmium?
[Xe] 6s² 4f¹⁴ 5d⁶. In shells that is 2, 8, 18, 32, 14, 2.
How many valence electrons does osmium have?
Osmium is a transition metal, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is osmium on the periodic table?
In group 8, period 6, in the d-block. It is a transition metal.
