Neon

Neon, ₁₀Ne

Neon
Appearance	colorless gas exhibiting an orange-red glow when placed in an electric field
Standard atomic weight Ar°(Ne)
	20.1797±0.0006[1] 20.180±0.001 (abridged)[2]
Neon in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson He ↑ Ne ↓ Ar fluorine ← neon → sodium
Atomic number (Z)	10
Group	group 18 (noble gases)
Period	period 2
Block	p-block
Electron configuration	[He] 2s2 2p6
Electrons per shell	2, 8
Physical properties
Phase at STP	gas
Melting point	24.56 K ​(−248.59 °C, ​−415.46 °F)
Boiling point	27.104 K ​(−246.046 °C, ​−410.883 °F)
Density (at STP)	0.9002 g/L
when liquid (at b.p.)	1.207 g/cm3[3]
Triple point	24.556 K, ​43.37 kPa[4][5]
Critical point	44.4918 K, 2.7686 MPa[5]
Heat of fusion	0.335 kJ/mol
Heat of vaporization	1.71 kJ/mol
Molar heat capacity	20.79[6] J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 12 13 15 18 21 27
Atomic properties
Oxidation states	0
Ionization energies	1st: 2080.7 kJ/mol 2nd: 3952.3 kJ/mol 3rd: 6122 kJ/mol (more)
Covalent radius	58 pm
Van der Waals radius	154 pm
Spectral lines of neon
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered cubic (fcc) (cF4)
Lattice constant	a = 453.77 pm (at triple point)[7]
Thermal conductivity	49.1×10−3 W/(m⋅K)
Magnetic ordering	diamagnetic[8]
Molar magnetic susceptibility	−6.74×10−6 cm3/mol (298 K)[9]
Bulk modulus	654 GPa
Speed of sound	435 m/s (gas, at 0 °C)
CAS Number	7440-01-9
History
Prediction	William Ramsay (1897)
Discovery and first isolation	William Ramsay & Morris Travers[10][11] (1898)
Isotopes of neon v e
Main isotopes[12] Decay abun­dance half-life (t1/2) mode pro­duct 20Ne 90.5% stable 21Ne 0.27% stable 22Ne 9.25% stable
Category: Neon view talk edit | references

Neon is a chemical element; it has symbol Ne and atomic number 10. It is the second noble gas in the periodic table.^[13] Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of air.

Neon was discovered in 1898 alongside krypton and xenon, identified as one of the three remaining rare inert elements in dry air after the removal of nitrogen, oxygen, argon, and carbon dioxide. Its discovery was marked by the distinctive bright red emission spectrum it exhibited, leading to its immediate recognition as a new element. The name neon originates from the Greek word νέον, a neuter singular form of νέος (neos), meaning 'new'. Neon is a chemically inert gas, with no known uncharged neon compounds. Existing neon compounds are primarily ionic molecules or fragile molecules held together by van der Waals forces.

The synthesis of most neon in the cosmos resulted from the nuclear fusion within stars of oxygen and helium through the alpha-capture process. Despite its abundant presence in the universe and Solar System—ranking fifth in cosmic abundance following hydrogen, helium, oxygen, and carbon—neon is comparatively scarce on Earth. It constitutes about 18.2 ppm of Earth's atmospheric volume and a lesser fraction in the Earth's crust. The high volatility of neon and its inability to form compounds that would anchor it to solids explain its limited presence on Earth and the inner terrestrial planets. Neon’s high volatility facilitated its escape from planetesimals under the early Solar System's nascent Sun's warmth.

Neon's notable applications include its use in low-voltage neon glow lamps, high-voltage discharge tubes, and neon advertising signs, where it emits a distinct reddish-orange glow.^[14][15] This same red emission line is responsible for the characteristic red light of CategoriesAbstract/Art/Design, General