What is the order of melting point of group 18 elements?

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AIIMS BSc NURSING 2023 Memory-Based Paper

Answer 1

CONCEPT:

Melting Points of Group 18 Elements

Group 18 elements, also known as noble gases, have weak van der Waals forces between their atoms.
The melting points of these elements generally increase with an increase in atomic number.
This trend is due to the increase in the size of the atoms and the corresponding increase in the strength of van der Waals forces.

EXPLANATION:

Considering the noble gases in Group 18:
He, Ne, Ar, Kr, Xe
As we move down the group from helium (He) to xenon (Xe):
- The atomic size increases.
- The van der Waals forces between the atoms become stronger.
- As a result, the melting points increase.
The order of melting points from lowest to highest is:
- He < Ne < Ar < Kr < Xe

Therefore, the correct order of melting points of Group 18 elements is: He < Ne < Ar < Kr < Xe.