Radon
A radioactive noble gas that seeps from uranium-bearing rock.
Inside the Radon atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Radon atom step by step.
Electron configuration
[Xe] 4f14 5d10 6s2 6p6
A neutral Radon atom has 86 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Gas
- Melting point
- 202 K (-71 °C)
- Boiling point
- 212 K (-62 °C)
- Density
- 0.00973 g/cm³
- Electronegativity
- 2.2 Pauling
- Atomic radius
- 120 pm
- 1st ionization energy
- 1037 kJ/mol
- Category
- Noble gases
Discovery & naming
- Discovered
- 1899
- Discovered by
- Ernest Rutherford and Robert Owens
- Origin of name
- From radium, from which it forms.
Notable uses
Radon home testing; historically used in radiotherapy.
Where Radon comes from
Neutron star mergers
Occurs on Earth only as a fleeting decay product of uranium and thorium, so it inherits their r-process origin.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 86
- Atomic mass
- [222]
- Category
- Noble gases
- Group · Period
- 18 · 6
- Block
- p-block
- Shells
- 2 · 8 · 18 · 32 · 18 · 8