ආගන්

Argon,  ₁₈Ar

General properties
Pronunciation	/ˈɑːrɡɒn/ AR-gon
Appearance	colorless gas exhibiting a lilac/violet glow when placed in an electric field
Standard atomic weight (Ar, standard)	39.948(1)  (abridged)
Argon 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 Ne ↑ Ar ↓ Kr ක්ලෝරීන් ← argon → පොටෑසියම්
Atomic number (Z)	18
Group, period	group n/a, period {{{period}}}
Block	[[{{{block}}}-block]]
Electron configuration	{{{electron configuration}}}
Electrons per shell	2, 8, 8
Physical properties
Melting point	83.81 K ​(−189.34 °C, ​−308.81 °F)
Boiling point	87.302 K ​(−185.848 °C, ​−302.526 °F)
Density (at STP)	1.784 g/L
when liquid (at b.p.)	1.3954 g/cm3
Triple point	83.8058 K, ​68.89 kPa
Critical point	150.687 K, 4.863 MPa
Heat of fusion	1.18 kJ/mol
Heat of vaporization	6.53 kJ/mol
Molar heat capacity	20.85 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K)   47 53 61 71 87
Atomic properties
Electronegativity	Pauling scale: no data
Ionization energies	1st: 1520.6 kJ/mol 2nd: 2665.8 kJ/mol 3rd: 3931 kJ/mol (more)
Covalent radius	106±10 pm
Van der Waals radius	188 pm
Spectral lines
Miscellanea
Crystal structure	​face-centered cubic (fcc)
Speed of sound	323 m/s (gas, at 27 °C)
Thermal conductivity	17.72×10−3  W/(m·K)
Magnetic ordering	diamagnetic
Magnetic susceptibility	−19.6×10−6 cm3/mol
CAS Number	7440-37-1
History
Discovery and first isolation	Lord Rayleigh and William Ramsay (1894)
Main isotopes of argon
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 36Ar 0.334% 36Ar is stable with 18 neutrons 37Ar syn 35 d ε 37Cl 38Ar 0.063% 38Ar is stable with 20 neutrons 39Ar trace 269 y β− 39K 40Ar 99.604% 40Ar is stable with 22 neutrons 41Ar syn 109.34 min β− 41K 42Ar syn 32.9 y β− 42K

ආගන් යනු පරමාණුක ක්‍රමාංකය 18 වූ මූලද්‍රව්‍යයයි. එහි රසායනික සංකේතය Ar ය. ආගන් ඒක පරමාණුක වායුවකි. ආවර්තිතා වගුවේ VIII / 0 (8) කාණ්‍ඩයේ සිටී. ආගන් උච්ච වායුවකි. ආගන් හි ඉලෙට්‍රොනික වින්‍යාසය 2,8,8 වේ. ආවර්තය 3 වන අතර කාන්ඩය VIII / 0 වේ. අයනය නොසාදයි. ප්‍රධාන සංයුජතාව 0 වේ.