Meitnerium (Mt): Bohr Model, Protons, Neutrons & Electrons
Meitnerium is element number 109, a superheavy in group 9, period 7. Its atom has 109 protons, 169 neutrons and 109 electrons arranged in 7 shells: 2, 8, 18, 32, 32, 15, 2.
- 109 protons
- 169 neutrons
- 109 electrons
Protons, neutrons and electrons in meitnerium
Le atomic number of meitnerium is 109, so every meitnerium atom has 109 protons. A neutral atom has the same number of electrons, 109. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For meitnerium-278, that is 278 − 109 = 169 neutrons. Every isotope of meitnerium is radioactive; 278 is the mass number of its most stable one.
How to draw the Bohr model of meitnerium
- Draw the nucleus and write 109 p⁺ et 169 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 15 electrons on it.
- Draw the seventh shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 32 + 15 + 2 = 109 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, 15, 2) is the one to draw.
Electron configuration
The electron configuration of meitnerium is [Rn] 7s² 5f¹⁴ 6d⁷. As a superheavy it fills an inner d-subshell, and its common ion is variable.
Key facts about meitnerium
| Symbol | Mt |
|---|---|
| Atomic number | 109 |
| Relative atomic mass | [278] |
| Group · period · block | group 9 · period 7 · d-block |
| Type | Super lourd |
| State at 25 °C | unknown |
| Couches électroniques | 2, 8, 18, 32, 32, 15, 2 |
| Electron configuration | [Rn] 7s² 5f¹⁴ 6d⁷ |
| Électrons de valence | varies (outer shell: 2) |
| Common ion | — |
| Electronegativity (Pauling) | — |
| First ionisation energy | — |
| Atomic radius (empirical) | — |
Où meitnerium sits on the periodic table
Foire aux questions
How many protons, neutrons and electrons does meitnerium have?
Meitnerium has 109 protons and 109 electrons (atomic number 109). Its most common isotope, meitnerium-278, has 278 − 109 = 169 neutrons.
What is the electron configuration of meitnerium?
[Rn] 7s² 5f¹⁴ 6d⁷. In shells that is 2, 8, 18, 32, 32, 15, 2.
How many valence electrons does meitnerium have?
Meitnerium is a superheavy, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is meitnerium on the periodic table?
In group 9, period 7, in the d-block. It is a superheavy.
