The noble gas which is radioactive is
- Argon
- Helium
- Radon
- Xenon
The Correct Option is C
Approach Solution - 1
Approach Solution -2
Radon is the only noble gas that is radioactive. It is a colourless, odourless and also tasteless gas. It is a noble gas and belongs to group 18. It has an inert nature because of the fully filled electrons.
Radon is formed by the decay product of the uranium and thorium that is found in the rocks and soil. When these elements undergo radioactive decay, Radon is generated in the chain process. It is present in the atmosphere in the form of traces.
Due to the radioactive nature, it has many health concerns, when present in at a high concentration. The elevated level can lead to lung cancer.
There are several isotopes of Radon, among them both Radon-222 and Radon- 220 are radioactive. They are formed during the chain decay process of uranium and thorium respectively. They emit radiation in the form of alpha particles during the decay.
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Notes on Group 18 Elements
Concepts Used:
Group 18 Elements
The Group 18 elements, also known as noble gases except for Helium, are inert in nature because they have completely filled ns2 np6 electronic configuration in their valence shells. These gases also have high ionization enthalpy and more positive electron gain enthalpy. All these elements are chemically unreactive i.e. they don’t form many compounds.
Group 18 Elements consist of six elements. They are as mentioned below:
- Helium (He)
- Neon (Ne)
- Argon (Ar)
- Krypton (Kr)
- Xenon (Xe)
- Radon (Rn)
Electronic Configuration:
The electronic configuration of Group 18 Elements along with their symbol and atomic number is given in the tabulated form below:
Trends in the Atomic Properties:
- Atomic Radius: The nuclear radii increment on moving down the group with increasing nuclear number. This is a result of the expansion of another shell at each progressive element on moving down the group.
- Electron Gain Enthalpy: Group 18 elements exhibit very stable electronic configurations. They do not have any tendency to accept an electron.
- Ionisation Potential: They have high ionisation potentials, thanks to their closed electronic configurations. This value decreases on moving down the group due to an expansion in the nuclear size.