22.6.1 Properties of Noble Gases Flashcards
1
Q
Properties of Noble Gases
A
- The noble gases, group 18 of the periodic table, have a low electron affinity and do not readily form compounds.
- Each of the noble gases has uses except for radon, which is dangerous because of its radioactivity.
2
Q
note
A
- The noble gases, group 18 of the periodic table, have a low electron affinity and do not readily form compounds.
- The noble gases are isolated from the atmosphere by liquefying air and separating each gas through fractional distillation. Helium is not present in the atmosphere because it is lighter than air, but it is formed as a product of radioactive decay and is found in large subterranean reservoirs also occupied by natural gas.
- The noble gases are relatively inert. But it is possible to form compounds with xenon, the gas with the lowest ionization energy. The fluorides of xenon all have negative enthalpies, are stable compounds and are solids at room temperature. The oxides of xenon all have positive enthalpies, are unstable and will decompose over time.
- Each of the noble gases has uses except for radon, which is dangerous because of its radioactivity.
- Helium is used as a refrigerant because it liquifies at a very low temperature (4.2 K) and to fill balloons because it is lighter than air. Neon is used as one of the gases to fill neon-light tubes. Argon is used as an inert filler for tungsten lamp bulbs and for the same reason in the space between panes in double-paned windows. Xenon and krypton are used as light emitters in flash devices.
- Radon is little-studied because of its radioactivity. It poses a danger in the basements of houses located in areas with large concentrations of natural radioisotopes in the ground. As a gas it would be relatively innocuous, but it has a short half-life (t 1/2 = 3.8 d) and decays to form polonium-216 ( 216 Po). 216 Po is also an alpha-emitter and is a solid that will remain in the body, unlike the original radon atoms. Basements containing high concentrations of radon must be vented to keep them safe.
3
Q
Which of the following is a common source for radon?
A
Radioactive decay
4
Q
Which of the following is TRUE about XeF2?
A
It is a stable compound
5
Q
Which of the following is a noble gas?
A
Argon
6
Q
What noble gas is produced by alpha decay?
A
Helium
7
Q
What is the common source for helium?
A
Natural gas wells
8
Q
What type of radioactive decay does radon undergo?
A
Alpha
9
Q
Why are the noble gases not generally reactive?
A
They have a filled outer electron shell.
10
Q
Which of the following is TRUE regarding xenon oxyfluorides?
A
They are unstable
11
Q
Which is a common source of argon?
A
Air
12
Q
Which of the following is not a noble gas?
A
Nitrogen
