Oganesson (Og): electron configuration, atomic mass and facts
Oganesson (Og) is element 118 of the periodic table, a noble gas (predicted) in period 7, group 18. Its electron configuration is [Rn] 5f14 6d10 7s2 7p6, with electrons arranged in shells 2, 8, 18, 32, 32, 18, 8, and its most stable isotope has mass number 294.
💡 The heaviest element known. Only a handful of atoms have ever been made.
▶ Watch Oganesson’s electrons orbit in the interactive periodic tableOganesson at a glance
| Symbol | Og |
|---|---|
| Atomic number | 118 |
| Atomic mass | [294] u (most stable isotope) |
| Category | Noble gas (predicted) |
| Group | 18 |
| Period | 7 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 7s2 7p6 |
| Noble-gas shorthand | [Rn] 5f14 6d10 7s2 7p6 |
| Electrons per shell | 2, 8, 18, 32, 32, 18, 8 |
| Outer-shell electrons | 8 |
| Electronegativity (Pauling) | — |
| State at 20 °C | Unknown (only a few atoms made) |
Where is Oganesson on the periodic table?
Oganesson is in period 7, group 18, in the p-block. The period number matches its 7 electron shells, and the block names the subshell its last electrons fill. In the same group, Radon sits directly above it. Elements in one group have the same number of outer-shell electrons (8 here), which is why they react in similar ways.
How to work out the electron configuration of Oganesson
Put 118 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p⁶ (10), 3s² (12), 3p⁶ (18), 4s² (20), 3d¹⁰ (30), 4p⁶ (36), 5s² (38), 4d¹⁰ (48), 5p⁶ (54), 6s² (56), 4f¹⁴ (70), 5d¹⁰ (80), 6p⁶ (86), 7s² (88), 5f¹⁴ (102), 6d¹⁰ (112), 7p⁶ (118). In shorthand, [Rn] stands for the 86 electrons of radon, giving [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶.
Frequently asked questions
What is the electron configuration of Oganesson?
The electron configuration of Oganesson (Og) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 7s2 7p6. In noble-gas shorthand it is written [Rn] 5f14 6d10 7s2 7p6.
How many electrons does Oganesson have in each shell?
Oganesson has 118 electrons arranged in shells as 2, 8, 18, 32, 32, 18, 8. It has 8 electrons in its outer shell.
What is the atomic mass of Oganesson?
Oganesson has no stable isotopes. Its most stable isotope has a mass number of 294.
Is Oganesson a metal?
No. Oganesson is a noble gas (predicted).
Explore nearby elements
More noble gass: Helium, Neon, Argon, Krypton, Xenon, Radon. See all elements on the periodic table.