Group 18
By Jon Alter, Parker Balduf, Shannon Hupert, and Julia Lantier
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.
Which elements belong to the group?
2
10
Helium
36
18
Neon
54
Krypton
Argon
86
Xenon
Rn
Radon
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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
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
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Properties
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
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
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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

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
Neon signs, but only red ones contain pure Neon
 Cryogenic refrigerate (as a liquid)
 High Voltage Indicators
 Lightning Arresters
 Television tubes
 Diving Equipment
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• 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: 0.002 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
• 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: 0.003 g/cmᶟ
• One of the rarest gases in the Earth’s atmosphere
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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 0.086 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
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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