Argon (18)

Argon is a colorless and odorless gas present to a very small extent in the atmosphere. Argon is very inert (indeed it is referred to as one of the noble gases) and is not known to form true chemical compounds. It makes a good atmosphere for working with air-sensitive materials since it is heavier than air and less reactive than N2. Today, the chemical symbol for argon is Ar but until 1957 its symbol was simply A.

•Name: Argon
•Symbol: Ar
•Atomic number: 18
•Atomic weight: 39.948
•Standard state: gas at 298 K
•CAS Registry ID: 7440-37-1
•Group in periodic table: 18
•Group name: Noble gas
•Period in periodic table: 3
•Block in periodic table: p-block
•Color: colorless
•Classification: Non-metallic

Historical information

Argon was discovered by Sir William Ramsay, Lord Rayleigh at 1894 in Scotland. Origin of name: from the Greek word "argos" meaning "inactive". Argon was discovered by Lord Rayleigh and Sir William Ramsay in 1894. It was isolated by examination of the residue obtained by removing nitrogen, oxygen, carbon dioxide, and water from clean air. In fact, air contains less than 1% argon. The atmosphere of Mars contains less than 2% argon. It was recognized by the characteristic lines in the red end of the spectrum.

Physical properties

•Melting point: 83.8 [or -189.3 °C (-308.7 °F)] K
•Boiling point: 87.3 [or -185.8 °C (-302.4 °F)] K
•Density of solid: 1616 kg m-3

Orbital properties

•Ground state electron configuration: [Ne].3s2.3p6
•Shell structure: 2.8.8
•Term symbol: 1S0
•Pauling electronegativity: no data (Pauling units)

Isolation

Argon is present to a small extent in the atmosphere and is obtained as a byproduct from the liquefaction and separation of air. This would not normally be carried out in the laboratory and argon is available commercially in cylinders at high pressure.

Interesting Facts:

1. Sir William Ramsay, with the help of Lord Rayleigh, discovered it in Scotland in the year 1894.

2. It emits light when it is electronically excited.

3. It is the most abundant of the rare gases.

4. It is used in light bulbs.

5. It is in the same group as neon.

6. Its name comes from the Greek word “argos”. “Argos” means inactive.

7. Approximately .94% of the earth’s atmosphere contains it.

8. Around 1.6% of Mar’s atmosphere contains argon.

9. It is used in the arc welding and cutting process.

10. It is in the same group as xenon.

11. It is used in plasma globes.

12. It is used in lasers.

13. It is created when potassium in the earth’s crust decays.

14. It is used in the process of dating ground water.

15. It is used in glow tubes.

16. It is a prospective atmosphere for the growth of germanium and silicon crystals.

17. It has a half-life of thirty-five days.

18. It does not have any true compounds.

19. It does not have a color.

20. It is used in fluorescent tubes.

21. It is not found in any compounds.

22. It is in the same group as krypton.

23. It is two and a half times more soluble in water than in nitrogen.

24. It is the third most abundant gas in the earth’s atmosphere.

25. It is nearly as soluble as oxygen.

26. Its most exotic use is in the tires of luxurious cars.

27. It is used in photo tubes.

28. It does not have an odor.

29. In 1785, suspected to be present in the air.

30. It is used in radio vacuum tubes.

31. It costs fifty cents for every one-hundred grams.

32. 750,000 tons of it produced every year.

33. It is approximately 1.4 times as heavy as air.

34. It does not have a taste.

35. It is in the same group as helium.

36. It is a nontoxic gas.

37. It produces a pale blue-violet light when it is electrically excited.

38. It is used in the process of manufacturing high quality stainless steels.

39. It is used in the process of producing impurity-free silicon crystals.

40. It is produced in conjunction with the manufacture of high purity oxygen.

41. Its boiling point is very close to that of oxygen.

42. Its atomic mass is 39.948 atomic mass units.

43. Its density is 1.784 grams per cubic centimeter.

44. Its period is three.

45. It is often used as a shield gas against oxidation.

46. It is in the same group as radon