The noble gas which shows abnormal behaviour in the liquid state is
- Ar
- Xe
- He
- Kr
The Correct Option is C
Approach Solution - 1
Approach Solution -2
Ans: Among the noble gases in the question, Helium.
Helium is the second lightest noble gas and remains in the gaseous state at the standard atmospheric pressure and temperature. Unlike He, all the other noble gases tend to liquify under the normal condition. Helium can be condensed to the liquid state at a very low temperature, that is close to absolute zero. This process of conversion of gas into liquid is called liquefaction.
Some of the characteristics properties that are attained by Helium at liquid state is as follows:
Zero viscosity: Liquid helium will exhibit at almost zero viscosity. It will flow with almost no resistance. This property of helium is called superfluidity. Among the isotopes of helium present, Helium-4 are the most common isotopes of helium that will undergo the phase phase transition below 2.17 K.
Non classical behaviour: non classical behaviour is observed in the thermal properties of helium. At low temperatures, the heat capacity decreases rather than
increasing. This phenomenon, known as the "lambda point," occurs at around 2.17 Kelvin.
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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.