Meitnerium (Mt)
Meitnerium is element 109, a transition metal in group 9, period 7. A neutral atom has 109 protons, 168 neutrons and 109 electrons, 2 of them valence electrons. Many of its properties are predicted, because only a few atoms have ever been made.
Transition metal- Atomic number
- 109
- Atomic mass
- [277] u
- Valence electrons
- 2*
- Protons · neutrons
- 109 · 168
- Electrons per shell
- 2, 8, 18, 32, 32, 15, 2
- At room temperature
- —
Bohr model of meitnerium
The Bohr model draws meitnerium as a nucleus of 109 protons and 168 neutrons, with its 109 electrons on 7 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 32 in shell 4, 32 in shell 5, 15 in shell 6, 2 in shell 7. Press Build the atom to watch the shells fill from the inside out. The outer ring (the Q shell) is dashed: the electrons there are the ones that take part in chemistry.
Real electrons don't travel in neat circles. They live in fuzzy orbitals, shown below, but the Bohr picture is the quickest way to count shells and valence electrons.
Electron configuration of meitnerium
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁷
Short form (noble gas notation): [Rn] 7s² 5f¹⁴ 6d⁷. The [Rn] stands for the electrons of radon, the noble gas before it.
This configuration is predicted from calculations; it has not been measured.
How many valence electrons does meitnerium have?
Meitnerium has 2 valence electrons.
Meitnerium is a transition metal, so its valence electrons are less clear-cut than for main-group elements. It has 2 electrons in its outermost shell (shell 7), and electrons in its inner d subshell can also take part in bonding.
Protons, neutrons and electrons
| Protons | 109 | equal to the atomic number |
|---|---|---|
| Electrons | 109 | equal to the protons in a neutral atom |
| Neutrons | 168 | mass number 277 − 109 protons (for its longest-lived isotope, Mt-277) |
Atoms of the same element can have different numbers of neutrons (isotopes). The count above uses the rounded atomic mass, the way it's taught in class.
Meitnerium properties
| Symbol | Mt |
|---|---|
| Category | Transition metal |
| Group · period · block | 9 · 7 · d |
| Atomic mass | [277] u |
| State at 25 °C | solid |
| Melting point | — |
| Boiling point | — |
| Density | — |
| Electronegativity (Pauling) | — |
| Atomic radius | — |
| First ionization energy | — |
| Electron affinity | — |
| Oxidation states | 9, 8, 6, 4, 3, 1 |
| Common ion charge | 9, 8 |
| Discovered | 1982 by Gesellschaft für Schwerionenforschung |
Where meitnerium sits on the periodic table
Group 9: Cobalt, Rhodium, Iridium.
Questions about meitnerium
How many valence electrons does meitnerium have?
Meitnerium has 2 valence electrons in its outer shell; inner d or f electrons can also bond.
How many protons, neutrons and electrons does meitnerium have?
A neutral meitnerium atom has 109 protons and 109 electrons. Its most common form has about 168 neutrons (mass number 277 − 109 protons).
What is the electron configuration of meitnerium?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁷, written in short form as [Rn] 7s² 5f¹⁴ 6d⁷. This configuration is predicted, not measured.
What does the Bohr model of meitnerium look like?
A nucleus of 109 protons and 168 neutrons, circled by 7 electron shells holding 2, 8, 18, 32, 32, 15, 2 electrons.
What is the atomic number of meitnerium?
109. The atomic number is the number of protons in the nucleus, and it is what makes an atom meitnerium.