Ruthenium (Ru): Bohr Model, Protons, Neutrons & Electrons
Ruthenium is element number 44, a transition metal in group 8, period 5. Its atom has 44 protons, 58 neutrons and 44 electrons arranged in 5 shells: 2, 8, 18, 15, 1.
Protons, neutrons and electrons in ruthenium
The atomic number of ruthenium is 44, so every ruthenium atom has 44 protons. A neutral atom has the same number of electrons, 44. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For ruthenium-102, that is 102 − 44 = 58 neutrons. Ruthenium has 7 stable isotopes, with 52, 54, 55, 56, 57, 58, 60 neutrons.
How to draw the Bohr model of ruthenium
- Draw the nucleus and write 44 p⁺ and 58 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 15 electrons on it.
- Draw the fifth shell and put 1 electron on it.
- Check: 2 + 8 + 18 + 15 + 1 = 44 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, 15, 1) is the one to draw.
Electron configuration
The electron configuration of ruthenium is [Kr] 5s¹ 4d⁷. As a transition metal it fills an inner d-subshell, and its common ion is Ru³⁺.
Key facts about ruthenium
| Symbol | Ru |
|---|---|
| Atomic number | 44 |
| Relative atomic mass | 101.07 |
| Group · period · block | group 8 · period 5 · d-block |
| Type | Transition Metal |
| State at 25 °C | solid |
| Electron shells | 2, 8, 18, 15, 1 |
| Electron configuration | [Kr] 5s¹ 4d⁷ |
| Valence electrons | varies (outer shell: 1) |
| Common ion | Ru³⁺ |
| Electronegativity (Pauling) | 2.20 |
| First ionisation energy | 7.36 eV (710 kJ/mol) |
| Atomic radius (empirical) | 130 pm |
Where ruthenium sits on the periodic table
Frequently asked questions
How many protons, neutrons and electrons does ruthenium have?
Ruthenium has 44 protons and 44 electrons (atomic number 44). Its most common isotope, ruthenium-102, has 102 − 44 = 58 neutrons.
What is the electron configuration of ruthenium?
[Kr] 5s¹ 4d⁷. In shells that is 2, 8, 18, 15, 1.
How many valence electrons does ruthenium have?
Ruthenium is a transition metal, so its valence electrons are spread over two shells; its outermost shell holds 1.
Where is ruthenium on the periodic table?
In group 8, period 5, in the d-block. It is a transition metal.
