Rhenium (Re)
Rhenium is element 75, a transition metal in group 7, period 6. A neutral atom has 75 protons, 111 neutrons and 75 electrons, 2 of them valence electrons.
Transition metal- Atomic number
- 75
- Atomic mass
- 186.21 u
- Valence electrons
- 2*
- Protons · neutrons
- 75 · 111
- Electrons per shell
- 2, 8, 18, 32, 13, 2
- At room temperature
- solid
Bohr model of rhenium
The Bohr model draws rhenium as a nucleus of 75 protons and 111 neutrons, with its 75 electrons on 6 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 32 in shell 4, 13 in shell 5, 2 in shell 6. Press Build the atom to watch the shells fill from the inside out. The outer ring (the P 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 rhenium
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d⁵
Short form (noble gas notation): [Xe] 6s² 4f¹⁴ 5d⁵. The [Xe] stands for the electrons of xenon, the noble gas before it.
How many valence electrons does rhenium have?
Rhenium has 2 valence electrons.
Rhenium 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 6), and electrons in its inner d subshell can also take part in bonding.
Protons, neutrons and electrons
| Protons | 75 | equal to the atomic number |
|---|---|---|
| Electrons | 75 | equal to the protons in a neutral atom |
| Neutrons | 111 | mass number 186 − 75 protons |
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.
Rhenium properties
| Symbol | Re |
|---|---|
| Category | Transition metal |
| Group · period · block | 7 · 6 · d |
| Atomic mass | 186.21 u |
| State at 25 °C | solid |
| Melting point | 3,459 K (3,190 °C, 5,770 °F) |
| Boiling point | 5,869 K (5,600 °C, 10,100 °F) |
| Density | 20.8 g/cm³ |
| Electronegativity (Pauling) | 1.9 |
| Atomic radius | 217 pm |
| First ionization energy | 7.88 eV |
| Electron affinity | 0.15 eV |
| Oxidation states | +7, +6, +4 |
| Common ion charge | +7, +6 |
| Discovered | 1925 by Masataka Ogawa |
Where rhenium sits on the periodic table
Group 7: Manganese, Technetium, Bohrium.
Questions about rhenium
How many valence electrons does rhenium have?
Rhenium has 2 valence electrons in its outer shell; inner d or f electrons can also bond.
How many protons, neutrons and electrons does rhenium have?
A neutral rhenium atom has 75 protons and 75 electrons. Its most common form has about 111 neutrons (mass number 186 − 75 protons).
What is the electron configuration of rhenium?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d⁵, written in short form as [Xe] 6s² 4f¹⁴ 5d⁵.
What does the Bohr model of rhenium look like?
A nucleus of 75 protons and 111 neutrons, circled by 6 electron shells holding 2, 8, 18, 32, 13, 2 electrons.
What is the atomic number of rhenium?
75. The atomic number is the number of protons in the nucleus, and it is what makes an atom rhenium.