Elements Group 18, Helium family, noble gases
Home    Elements   Group 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  L  A

The noble gases (historically also the inert gases) make up a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). Oganesson (Og) is variously predicted to be a noble gas as well or to break the trend due to relativistic effects; its chemistry has not yet been investigated.

For the first six periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are typically highly unreactive except when under particular extreme conditions. The inertness of noble gases makes them very suitable in applications where reactions are not wanted.

The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons is considered to be "full", giving them little tendency to participate in chemical reactions, and it has been possible to prepare only a few hundred noble gas compounds. The melting and boiling points for a given noble gas are close together, differing by less than 10 °C; that is, they are liquids over only a small temperature range.

Neon, argon, krypton, and xenon are obtained from air in an air separation unit using the methods of liquefaction of gases and fractional distillation. Helium is sourced from natural gas fields which have high concentrations of helium in the natural gas, using cryogenic gas separation techniques, and radon is usually isolated from the radioactive decay of dissolved radium, thorium, or uranium compounds.


G 18
2
He
10
Ne
18
Ar
36
Kr
54
Xe
86
Rn
118
Og
  
Helium He
  colorless noble gas, 2nd most abundant
  atomic numb 2
  atomic mass 4.003
  electron shell 2
  melt point −272.20°C
  boil point −268.928°C
  Stable isotopes ³He ⁴He

Neon Ne
  colorless inert monatomic gas
  atomic numb 10
  atomic mass 20.18
  electron shell 2,8
  melt point −248.59°C
  boil point −246.046°C
  Stable isotopes 20,21,22

Argon Ar
  colorless inert monatomic gas
  atomic numb 18
  atomic mass 39.948
  electron shell 2,8,8
  melt point –189.34°C
  boil point −185.848°C
  density (STP) 1.784 g/L
    liquid 1.3954 g/cm³
  Heat of fusion: 1.18 kJ/mol
  Heat of vaporization: 6.53 kJ/mol
  heat capacity: 20.85 J/(mol·K)
  Stable isotopes 36,38,40

  
Krypton Kr
  colorless odorless noble gas
  atomic numb 36
  atomic mass 83.798
  electron shell 2,8,18,8
  melt point −157.37°C
  boil point −153.415°C
  density 3.749 g/L
    liquid 2.413 g/cm³
  Heat of fusion: 1.64 kJ/mol
  Heat of vaporization: 9.08 kJ/mol
  heat capacity: 20.95 J/(mol·K)
  Stable isotopes 79,80,82,83,84,86

Xenon Xe
  colorless, dense, noble gas
  atomic numb 54
  atomic mass 131.29
  electron shell 2,8,18,18,8
  melt point −111.75°C
  boil point −108.099°C
  density 5.894 g/L
    liquid 2.942 g/cm³
  Heat of fusion: 2.27 kJ/mol
  Heat of vaporization: 12.64 kJ/mol
  heat capacity: 21.01 J/(mol·K)
  Stable isotopes 124,26,28-32,34

Radon Rn 86 222 2,8,18,32,18,8

Oganesson Og 118 294 2,8,18,32,32,18,8

Home

Area, Volume
Atomic Mass
Black Body Radiation
Boolean Algebra
Calculus
Capacitor
Center of Mass
Carnot Cycle
Charge
Chemistry
Circuits
Complex numbers
Constants
Curves
deciBell
Density
Electronics
Elements
Flow in fluids
Fourier's Law
Gases
Gravitation
Greek Alphabet
Horizon Distance
Interest
Magnetics
Math   Trig
Math, complex
Maxwell's Eq's
Motion
Newton's Laws
Octal/Hex Codes
Orbital Mechanics
Particles
Parts, Analog IC
  Digital IC   Discrete
Pendulum
Pressure
Prime Numbers
Questions
Radiation
Refraction
Relativistic Motion
Resistance, Resistivity
Rotation
Series
SI (metric) prefixes
Skin Effect
Specific Heat
Springs
Stellar magnitude
Thermal
Thermal Conductivity
Thermal Expansion
Thermodynamics
Trigonometry
Units, Conversions
Vectors
Volume, Area
Water
Wave Motion
Wire, Cu   Al   metric
Young's Modulus