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Periodic Table of Elements

Element Argon - Ar

Comprehensive data on the chemical element Argon is provided on this page; including scores of properties, element names in many languages, most known nuclides of Argon. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.

Argon Menu

• Argon Page One
  • Overview of Argon
  • Argon's Name in Other Languages
  • Atomic Structure of Argon
  • Chemical Properties of Argon
  • Physical Properties of Argon
  • Regulatory / Health
  • Who/When/Where/How
• Argon Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides

Overview of Argon

• Atomic Number: 18
• Group: 18
• Period: 3
• Series: Noble Gasses

Argon's Name in Other Languages

• Latin: Argon
• Czech: Argon
• Croatian: Argon
• French: Argon
• German: Argon - r
• Italian: Argo
• Norwegian: Argon
• Portuguese: Argônio
• Russian: Аргон
• Spanish: Argón
• Swedish: Argon

Atomic Structure of Argon

• Atomic Radius: 0.88Å
• Atomic Volume: 28.5cm³/mol
• Covalent Radius: 0.98Å
• Cross Section (Thermal Neutron Capture)σ_a/barns: 0.675
• Crystal Structure: Cubic face centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶

• Electrons per Energy Level: 2,8,8

  Shell Model
  

• Ionic Radius:
• Filling Orbital: 3p⁶
• Number of Electrons (with no charge): 18
• Number of Neutrons (most common/stable nuclide): 22
• Number of Protons: 18
• Oxidation States: 0
• Valence Electrons: 3s²p⁶

  Electron Dot Model
  

Chemical Properties of Argon

• Electrochemical Equivalent:
• Electron Work Function:
• Electronegativity: N/A (Pauling); 3.2 (Allrod Rochow)
• Heat of Fusion: 1.188kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 15.759
  • Second: 27.629
  • Third: 40.74
• Valence Electron Potential (-eV):

Physical Properties of Argon

• Atomic Mass Average: 39.948
• Boiling Point: 87.45K -185.7°C -302.3°F
• Coefficient of lineal thermal expansion/K^-1: N/A
• Conductivity

  Electrical:
  Thermal: 0.0001772 W/cmK

• Density: 1.7824g/L @ 273K & 1atm
• Description:

  Colorless, odorless, tasteless noble gas.

• Enthalpy of Fusion: 1.18 kJ/mole
• Enthalpy of Vaporization: 6.43 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Heat of Vaporization: 6.447kJ/mol
• Melting Point: 83.96K -189.19°C -308.54°F
• Molar Volume: 24.2 cm³/mole
• Optical Refractive Index: 1.000281
• Physical State (at 20°C & 1atm): Gas
• Specific Heat: 0.52J/gK

Regulatory / Health

• CAS Number
  • 7440-37-1
• UN/NA ID and ERG Guide Number
  • UN1006  
• RTECS: CF2300000
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: trace
  • Bone/p.p.m: nil
  • Liver/p.p.m: nil
  • Muscle/p.p.m: nil
  • Daily Dietary Intake: n/a
  • Total Mass In Avg. 70kg human: n/a

Who / Where / When / How

• Discoverer: Sir William Ramsey, Lord Baron Rayleigh
• Discovery Location: Bristol England (Ramsey)/London England (Rayleigh)
• Discovery Year: 1894
• Name Origin:

  Greek: Argos (inactive).

• Abundance of Argon:
  • Earth's Crust/p.p.m.: 1.2
  • Seawater/p.p.m.: 0.45
  • Atmosphere/p.p.m.: 9300
  • Sun (Relative to H=1E¹²): 1000000
• Sources of Argon:

  Argon makes up 1% of the air and is isolated by removing nitrogen, oxygen, carbon dioxide and water from air. Argon is constantly being formed from the radioactive decay of K-40 (an isotope of potassium). of radioactive potassium-40. World wide commercial production is around 700,000 tons per year.

• Uses of Argon:

  Argon is used for lighting. It may also be used to provide an inert atmosphere for certain projects when explosion or other forms of oxidation may pose a problem. Also used in "Geiger" counters, which measure radiation levels.

• Additional Notes:

Argon Menu

• Argon Page One
  • Overview of Argon
  • Argon's Name in Other Languages
  • Atomic Structure of Argon
  • Chemical Properties of Argon
  • Physical Properties of Argon
  • Regulatory / Health
  • Who/When/Where/How
• Argon Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides

References

A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.

Related Resources

• Anatomy of the Atom
  Answers many questions regarding the structure of atoms.
• Molarity, Molality and Normality
  Introduces stoichiometry and explains the differences between molarity, molality and normality.
• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

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Kenneth Barbalace. Periodic Table of Elements - Argon - Ar. EnvironmentalChemistry.com. 1995 - 2024. Accessed on-line: 11/21/2024
https://EnvironmentalChemistry.com/yogi/periodic/Ar.html
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