Neon (Ne)
Element 10 · Noble gas · atomic mass 20.18 u · group 18, period 2
Electron shells: 2, 8
Neon is an inert noble gas that glows a distinctive red-orange when electricity passes through it. It is chemically inert to the point that no stable neon compound has ever been made.
Only true neon signs glow red-orange — every other colour comes from a different gas or coating.
- Atomic number
- 10
- Atomic mass
- 20.18 u
- Electron configuration
- [He] 2s² 2p⁶
- Group · period · block
- 18 · 2 · p
- Oxidation states
- 0
- Electronegativity
- Not measured
- Melting point
- -249 °C
- Boiling point
- -246 °C
- Density
- 0.0008999 g/cm³
- State at 20 °C
- Gas
- Appearance
- Colourless gas; red-orange glow when excited
- Discovered
- William Ramsay and Morris Travers, 1898
10 protons, and 10 electrons when neutral
IUPAC standard atomic weight
Noble gases
What Neon is used for
- Neon signage and indicator lamps
- Excimer lasers for chip lithography
- Cryogenic refrigerant
- High-voltage indicators
Atomic structure of Neon
A neutral neon atom has 10 protons and 10 electrons. Its most common isotope carries about 10 neutrons, which is where the mass number 20 comes from. Change the neutron count and you have a different isotope of neon; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8. In orbital notation that is [He] 2s² 2p⁶, leaving 8 valence electrons in the outer shell — the ones that do the chemistry.
3D electron orbitals
See where Neon's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Neon sits in the periodic table
Group 18, with full outer shells and almost no drive to react. Their inertness is exactly what makes them useful for shielding, lighting and cooling.
Discovery and naming
Neon was discovered by William Ramsay and Morris Travers in 1898. Its name comes from Greek neos, "new".
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Neon?
The standard atomic weight of Neon is 20.18 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Neon have?
Neon has 10 protons, because the atomic number is the proton count and that is what makes an atom Neon at all. A neutral Neon atom has the same number of electrons, 10. The neutron count varies by isotope; the most common one has about 10, since 20 − 10 = 10.
What is the electron configuration of Neon?
The electron configuration of Neon is [He] 2s² 2p⁶. Its electrons are arranged 2, 8 across 2 shells.
Is Neon a metal?
No. Neon is classified as a noble gas, on the right-hand side of the table where elements gain or share electrons rather than losing them.
What group and period is Neon in?
Neon is in group 18 (the noble gases), period 2, in the p-block. The group is its column and the period is its row.
What is the melting point of Neon?
Neon melts at -249 °C and boils at -246 °C. That puts it in the gases at everyday temperatures.
What is Neon used for?
Neon signage and indicator lamps, Excimer lasers for chip lithography, Cryogenic refrigerant, High-voltage indicators. Neon is an inert noble gas that glows a distinctive red-orange when electricity passes through it.
Who discovered Neon, and where does its name come from?
Neon (Ne) was discovered by William Ramsay and Morris Travers in 1898. The name comes from Greek neos, "new".