Argon

Argon
18Ar
Ne ↑ Ar ↓ Kr Periodic table chlorine ← argon → potassium
Appearance
colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field Spectral lines of argon
General properties
Name, simbolo, kaiphan	argon, Ar, 18
Pronunciation	Plantilya:IPAc-en
Element category	gas nga halangdon
Group, period, block	18, 3, p
Standard atomic weight	39.948(1)
Electron configuration	[Ne] 3s2 3p6 2, 8, 8
History
Discovery	Lord Rayleigh and William Ramsay (1894)
First isolation	Lord Rayleigh and William Ramsay (1894)
Physical properties
Phase	gas
Density	(0 °C, 101.325 kPa) 1.784 g/L
Liquid density at b.p.	1.40 g·cm−3
Melting point	83.80 K, −189.35 °C, −308.83 °F
Boiling point	87.30 K, −185.85 °C, −302.53 °F
Triple point	83.8058 K (-189°C), 69 kPa
Critical point	150.87 K, 4.898 MPa
Heat of fusion	1.18 kJ·mol−1
Heat of vaporization	6.43 kJ·mol−1
Molar heat capacity	5R/2 = 20.786 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k at T (K)   47 53 61 71 87
Atomic properties
Oxidation states	0
Electronegativity	no data (Pauling scale)
Ionization energies (more)	1st: 1520.6 kJ·mol−1
	2nd: 2665.8 kJ·mol−1
	3rd: 3931 kJ·mol−1
Covalent radius	106±10 pm
Van der Waals radius	188 pm
Miscellanea
Crystal structure	face-centered cubic
Magnetic ordering	diamagnetic
Thermal conductivity	17.72x10-3  W·m−1·K−1
Speed of sound	(gas, 27 °C) 323 m·s−1
CAS registry number	7440–37–1
Most stable isotopes
Main article: Isotopes of argon
iso NA half-life DM DE (MeV) DP 36Ar 0.337% 36Ar is stable with 18 neutrons 37Ar syn 35 d ε 0.813 37Cl 38Ar 0.063% 38Ar is stable with 20 neutrons 39Ar trace 269 y β− 0.565 39K 40Ar 99.600% 40Ar is stable with 22 neutrons 41Ar syn 109.34 min β− 2.49 41K 42Ar syn 32.9 y β− 0.600 42K

Ang argon mao ang elementong kimiko sa talaang peryodiko nga may simbolo nga Ar ug kaiphan nga atomik 18. Ang argon mao ang gas nga halangdon.

Galeriya sa hulagway

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