Radon (Rn)
Radon is one of the densest gases known, about eight times heavier than air, so it tends to collect in basements.
Radon properties
- Atomic mass
- 222 u
- Category
- Noble gas
- Group
- 18
- Period
- 6
- Block
- p-block
- Melting point
- 202 K (-71.1 °C)
- Boiling point
- 211.3 K (-61.8 °C)
- Density
- 9.73 g/L
- Atomic radius
- 220 pm
- Ionization energy
- 10.745 eV
- Electron affinity
- —
- Radioactive
- Yes, no stable isotopes
- Discovered
- 1899
Radon electron configuration
- Electron configuration
- [Xe] 4f14 5d10 6s2 6p6
- Full electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6
- Electron shells
- 2 · 8 · 18 · 32 · 18 · 8
The electron configuration of Radon (Rn) is [Xe] 4f14 5d10 6s2 6p6. Its 86 electrons are arranged in shells as 2, 8, 18, 32, 18, 8.
Protons, neutrons and electrons in Radon
A neutral Radon atom has 86 protons and 86 electrons. Most Radon atoms have about 136 neutrons: the atomic mass rounded to 222, minus the atomic number 86.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Radon have?
8
Radon has 8 valence electrons in its outermost shell, shell 6. These are the electrons involved in chemical bonding.
Radon orbital diagram
Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations
Molar mass of Radon
222 g/mol
One mole of Radon atoms (6.022 × 10²³ atoms) has a mass of 222 grams. Use this value to convert between grams and moles.
Radon facts
- Radon is one of the densest gases known, about eight times heavier than air, so it tends to collect in basements.
- When cooled below its freezing point, radon glows with a bright yellow light that turns orange-red as the temperature drops further.
- Radon (Rn) has atomic number 86 and is a gas at room temperature. It was discovered in 1899.
Position in the periodic table
Radon is element 86, in period 6 and group 18 of the periodic table, in the p-block.
Uses of Radon
Radon has few practical uses today because it is radioactive and a health hazard. It was once sealed in small tubes, called seeds, to treat cancer with radiation, and scientists still measure it to trace groundwater and air movement. Most attention goes to testing for radon in homes, since it seeps from soil and rock and is the second leading cause of lung cancer after smoking.
Who discovered Radon?
In 1899 Ernest Rutherford and Robert Owens at McGill University in Montreal noticed a radioactive gas given off by thorium compounds, and in 1900 Friedrich Ernst Dorn in Germany found a similar gas released by radium. The name radon comes from radium.
Where does the name come from?
Radon gets its name from radium, the element whose radioactive decay produces it, with the ending -on borrowed from other noble gases such as argon and neon. Radium itself comes from the Latin radius, 'ray'.
Same group
Compare Radon
FAQ
What is the electron configuration of Radon?
The electron configuration of Radon (Rn) is [Xe] 4f14 5d10 6s2 6p6. Its 86 electrons are arranged in shells as 2, 8, 18, 32, 18, 8.
How many protons, neutrons and electrons does Radon have?
A neutral Radon atom has 86 protons and 86 electrons. Most Radon atoms have about 136 neutrons: the atomic mass rounded to 222, minus the atomic number 86.
How many valence electrons does Radon have?
Radon has 8 valence electrons in its outermost shell, shell 6. These are the electrons involved in chemical bonding.
What is the molar mass of Radon?
The molar mass of Radon is 222 g/mol. This is the same number as its atomic mass, 222 u.
Is Radon a metal?
No. Radon is a noble gas, so it is a nonmetal.
Is Radon radioactive?
Yes. Radon has no stable isotopes, so all of its atoms are radioactive and eventually decay into other elements.
Where is Radon on the periodic table?
Radon is element 86, in period 6 and group 18 of the periodic table, in the p-block.