Radon (Rn): electron configuration, atomic mass and facts
Radon (Rn) is element 86 of the periodic table, a noble gas in period 6, group 18. Its electron configuration is [Xe] 4f14 5d10 6s2 6p6, with electrons arranged in shells 2, 8, 18, 32, 18, 8, and its most stable isotope has mass number 222.
▶ Watch Radon’s electrons orbit in the interactive periodic tableRadon at a glance
| Symbol | Rn |
|---|---|
| Atomic number | 86 |
| Atomic mass | [222] u (most stable isotope) |
| Category | Noble gas |
| Group | 18 |
| Period | 6 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 |
| Noble-gas shorthand | [Xe] 4f14 5d10 6s2 6p6 |
| Electrons per shell | 2, 8, 18, 32, 18, 8 |
| Outer-shell electrons | 8 |
| Electronegativity (Pauling) | 2.2 |
| State at 20 °C | gas |
Where is Radon on the periodic table?
Radon is in period 6, group 18, in the p-block. The period number matches its 6 electron shells, and the block names the subshell its last electrons fill. In the same group, Xenon sits directly above it and Oganesson sits directly below 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 Radon
Put 86 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). In shorthand, [Xe] stands for the 54 electrons of xenon, giving [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶.
How electronegative is Radon?
Radon has a Pauling electronegativity of 2.2, ranking 17 of the 100 elements with a known value (fluorine is highest at 3.98). That is in the middle of the range.
Frequently asked questions
What is the electron configuration of Radon?
The electron configuration of Radon (Rn) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6. In noble-gas shorthand it is written [Xe] 4f14 5d10 6s2 6p6.
How many electrons does Radon have in each shell?
Radon has 86 electrons arranged in shells as 2, 8, 18, 32, 18, 8. It has 8 electrons in its outer shell.
What is the atomic mass of Radon?
Radon has no stable isotopes. Its most stable isotope has a mass number of 222.
Is Radon a metal?
No. Radon is a noble gas.
Explore nearby elements
More noble gass: Helium, Neon, Argon, Krypton, Xenon, Oganesson. See all elements on the periodic table.