Bohrium (Bh): Bohr Model, Protons, Neutrons & Electrons
Bohrium is element number 107, a superheavy in group 7, period 7. Its atom has 107 protons, 163 neutrons and 107 electrons arranged in 7 shells: 2, 8, 18, 32, 32, 13, 2.
Protons, neutrons and electrons in bohrium
The atomic number of bohrium is 107, so every bohrium atom has 107 protons. A neutral atom has the same number of electrons, 107. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For bohrium-270, that is 270 − 107 = 163 neutrons. Every isotope of bohrium is radioactive; 270 is the mass number of its most stable one.
How to draw the Bohr model of bohrium
- Draw the nucleus and write 107 p⁺ and 163 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 32 electrons on it.
- Draw the sixth shell and put 13 electrons on it.
- Draw the seventh shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 32 + 13 + 2 = 107 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, 32, 13, 2) is the one to draw.
Electron configuration
The electron configuration of bohrium is [Rn] 7s² 5f¹⁴ 6d⁵. As a superheavy it fills an inner d-subshell, and its common ion is variable.
Key facts about bohrium
| Symbol | Bh |
|---|---|
| Atomic number | 107 |
| Relative atomic mass | [270] |
| Group · period · block | group 7 · period 7 · d-block |
| Type | Superheavy |
| State at 25 °C | unknown |
| Electron shells | 2, 8, 18, 32, 32, 13, 2 |
| Electron configuration | [Rn] 7s² 5f¹⁴ 6d⁵ |
| Valence electrons | varies (outer shell: 2) |
| Common ion | — |
| Electronegativity (Pauling) | — |
| First ionisation energy | — |
| Atomic radius (empirical) | — |
Where bohrium sits on the periodic table
Frequently asked questions
How many protons, neutrons and electrons does bohrium have?
Bohrium has 107 protons and 107 electrons (atomic number 107). Its most common isotope, bohrium-270, has 270 − 107 = 163 neutrons.
What is the electron configuration of bohrium?
[Rn] 7s² 5f¹⁴ 6d⁵. In shells that is 2, 8, 18, 32, 32, 13, 2.
How many valence electrons does bohrium have?
Bohrium is a superheavy, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is bohrium on the periodic table?
In group 7, period 7, in the d-block. It is a superheavy.
