1. By Jon Alter, Parker Balduf, Shannon Hupert, and Julia Lantier
NOBLE GASES
Group 18
By Jon Alter, Parker Balduf, Shannon Hupert, and Julia Lantier

2. Name Origin
Used to be called inert gases, but other gases not included in this group are inert
“Noble gas”- derived from German word “edelgas” (“edili”= noble)
Alludes to the phrase “noble metals”= metals resistant to corrosion/oxidation. Thus noble refers to the gases’ low reactivity.

3. Which elements belong to the group?2 10 18
Helium
Neon
Argon Rn 36 54 86
Krypton
Xenon
Radon

4. General Characteristics
Gases at room temperature
Monatomic gases, meaning that they exist as single atoms
Colorless
Density increases as you move vertically down the group
Melting point increases as you move vertically down the group
Compared to other groups, very low melting points due to weak interatomic forces
Almost entirely unreactive- they are stable due to their full outer electron shell

5. Helium
Discovered in 1895
By Sir William Ramsay and independently by Per Teodor Cleve & Nils Abraham Langlet
In London, England and Uppsala, Sweden respectively
Named after ‘helios,’ the Greek word for the sun
First detected in Sun’s spectral
lines

6. The Properties of Helium
Values
Density
0.0002 g/cm3
Color
Colorless
Melting Point
Unknown 
Boiling Point
-269 oC
Locations on Earth
Atmosphere and underground
Abundance in the Universe
2nd most abundant

7. Helium Uses Cooling medium (e.g. in the Large Hadron Collider)
Filling airships and balloons
Helium-neon gas lasers (used to scan barcodes)
Arc Welding
Artificial atmospheres for
deep sea divers

8. Neon Discovered in 1898 By Sir William Ramsay and M.W. Travers
In London, England
Comes from the Greek word ‘neos,’ which means new
Found in an experiment of
evaporating solid argon under
reduced pressure

9. The Properties of Neon Properties Values Density 0.0008 g/cm3 Color
Colorless
Melting Point
-249 oC
Boiling Point
-246 oC
Locations on Earth
Atmosphere
Abundance in the Universe
5th most abundant

10. Neon Uses Neon signs, but only red ones contain pure Neon
Cryogenic refrigerate (as a liquid)
High Voltage Indicators
Lightning Arresters
Television tubes
Diving Equipment

11. Argon
Name origin: The name is derived from the Greek, 'argos', meaning idle.
Found in 1894 by Lord Rayleigh and William Ramsay
Was discovered as a result of trying to explain why the density of nitrogen extracted from air differed from that obtained by the decomposition of ammonia
Colorless and odorless gas
Melting point: -189° C
Boiling point: -186° C
Density: g/cmᶟ
There is no reactivity for argon because it is a noble gas.
Obtained from the air as a byproduct of oxygen and nitrogen production

12. Krypton
Name origin: The name is derived from the Greek 'kryptos', meaning hidden.
Discovered in 1898 by Sir William Ramsay and M.W. Travers
Does not react with anything but fluorine gas
Colorless, odorless gas
Melting point: -157° C
Boiling point: -153° C
Density: g/cmᶟ
One of the rarest gases in the Earth’s atmosphere

13. Xenon
Discovery date- 1898
Discovered by-Sir William Ramsay and M.W. Travers
Name origin-The name is derived from the Greek 'xenos' meaning stranger.
Characteristics:colorless, odorless, unreactive
Uses- Xenon is used in certain specialized light sources (electronic flash bulbs used by photographers, sunbed lamps ,and bactericidal lamps used in food preparation, ruby lasers), ion propulsion systems used in satellites, manufacture of 5-fluorouracil (a drug used to treat cancer)
Natural abundance: Xenon is present in the atmosphere at a concentration of parts per million by volume. It can also be found in the gases that evolve from certain mineral springs.
How it is obtained: extraction from liquid air.
Melting point
-112° C
Boiling point
-108° C
Density
0.005 g/cm3
Atomic number 54

14. Radon Discovery date- 1902 Discovered by- F.E. Dorn
Name origin-The name is derived from radium, as it was first detected as an emission from radium during radioactive decay.
Characteristics-Radon is a colorless and odorless gas. It is chemically inert, but radioactive.
Uses- Radon decays into radioactive polonium and alpha particles. This emitted radiation makes radon useful in cancer therapy.
How it is obtained- Radon is produced naturally from the decay of the isotope radium-226.
There is a detectable amount in the Earth’s atmosphere.
Melting point
-71o C
Boiling point
-61.7o C
Density
0.009 g/cm3
Atomic number 86