Nẹ́ọ̀nù

Nẹ́ọ̀nù ni ẹ́límẹ̀ntì kẹ́míkà kan tó ní àmí-ìdámọ̀ Ne àti nọ́mbà átọ̀mù 10. Ó wà nínú ẹgbẹ́ 18 (àwọn ẹ̀fúùfù abíire) lórí tábìlì ìdásìkò àwọn ẹ́límẹ̀ntì. Lábẹ́ àwọn ìṣẹ̀lẹ̀ déédé nẹ́ọ̀nù jẹ́ ẹ́fúùfù oníátọ̀mùkan aláìláwọ̀, aláìlóòórùn, ó jẹ́ ìdá méjì nínú mẹ́ta ìjẹ́kíki afẹ́fẹ́. Ó jé wíwárí (papọ̀ mọ́ kríptónì àti ksẹ́nọ́nù) ní 1898 gẹ́gẹ́bí ìkan nínú àwọn ẹ́límẹ̀ntì àìgbéra tósọ̀wọ́n tó ṣẹ́kù nínú afẹ́fẹ́ gbígbẹ, lẹ́yìn tí nítrójìn, ọ́ksíjìn, árgọ̀nù àti dìọ́ksídì kárbọ̀nù ti jẹ́ yíyọ kúrò. Nẹ́ọ̀nù ni ó jẹ́ èkejì nínú àwọn ẹ̀fúùfù àṣọ̀wọ́n mẹ́tẹ̀ẹ̀ta tó jẹ́ wíwárí, ó sí jẹ́ dídámọ̀ kíákíá bíi ẹ́límẹ̀ntì tuntun nítorí ìgbàjá-àwọ̀ ìtúsíta pupa rẹ̀. Orúkọ rẹ̀ wá láti ọ̀rọ̀ èdè Grííkì tó túmọ̀sí "ohun tuntun." Nẹ́ọ̀nù jẹ́ aláìgbéra bíi kẹ́míkà, kò sì lè dá àdàpọ̀ kẹ́míkà aláìní-àgbérù.

Nẹ́ọ̀nù, ₁₀Ne

Nẹ́ọ̀nù
Ìhànsójú	colorless gas exhibiting an orange-red glow when placed in a high voltage electric field
Ìwúwo átọ̀mù Ar, std(Ne)	20.1797(6)
Nẹ́ọ̀nù ní orí tábìlì àyè
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 fluorínì ← nẹ́ọ̀nù → sódíọ̀mù
Nọ́mbà átọ̀mù (Z)	10
Ẹgbẹ́	group 18 (noble gases)
Àyè	àyè 2
Àdìpọ̀	Àdìpọ̀-p
Ẹ̀ka ẹ́límẹ́ntì	Ẹ̀fúùfù abíire
Ìtò ẹ̀lẹ́ktrọ́nù	[He] 2s2 2p6
Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan	2, 8
Àwọn ohun ìní ara
Ìfarahàn at STP	ẹ̀fúùfù
Ìgbà ìyọ́	24.56 K ​(-248.59 °C, ​-415.46 °F)
Ígbà ìhó	27.07 K ​(-246.08 °C, ​-410.94 °F)
Kíki (at STP)	0.9002 g/L
when liquid (at b.p.)	1.207 g/cm3
Triple point	24.5561 K, ​43 kPa
Critical point	44.4 K, 2.76 MPa
Heat of fusion	0.335 kJ/mol
Heat of	1.71 kJ/mol
Molar heat capacity	5R/2 = 20.786 J/(mol·K)
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
energies	(more)
Covalent radius	58 pm
Van der Waals radius	154 pm
Color lines in a spectral range Spectral lines of nẹ́ọ̀nù
Other properties
Natural occurrence	primordial
Crystal structure	​(fcc)
Speed of sound	(gas, 0 °C) 435 m/s
Thermal conductivity	49.1x10-3  W/(m·K)
Magnetic ordering	diamagnetic
Bulk modulus	654 GPa
CAS Number	7440-01-9
History
Prediction	William Ramsay (1897)
Discovery	William Ramsay & Morris Travers (1898)
First isolation	William Ramsay & Morris Travers (1898)
Main isotopes of nẹ́ọ̀nù
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 20Ne 90.48% 20Ne is stable with 10 neutrons 21Ne 0.27% 21Ne is stable with 11 neutrons 22Ne 9.25% 22Ne is stable with 12 neutrons

During cosmic nucleogenesis of the elements, large amounts of neon are built up from the alpha-capture fusion process in stars. Although neon is a very common element in the universe and solar system (it is fifth in cosmic abundance after hydrogen, helium, oxygen and carbon), it is very rare on Earth. It composes about 18.2 ppm of air by volume (this is about the same as the molecular or mole fraction), and a smaller fraction in the crust. The reason for neon's relative scarcity on Earth and the inner (terrestrial) planets, is that neon forms no compounds to fix it to solids, and is highly volatile, therefore escaping from the planetesimals under the warmth of the newly-ignited Sun in the early Solar System. Even the atmosphere of Jupiter is somewhat depleted of neon, presumably for this reason.

Neon gives a distinct reddish-orange glow when used in either low-voltage neon glow lamps or in high-voltage discharge tubes or neon advertising signs. The red emission line from neon is also responsible for the well known red light of helium-neon lasers. Neon is used in a few plasma tube and refrigerant applications but has few other commercial uses. It is commercially extracted by the fractional distillation of liquid air. It is considerably more expensive than helium, since air is its only source.