The species Ar, K+ and Ca2+ contain the same number of electrons. In which order do their radii increase?

 

  Question:  From NCERT  | NEET    || [Difficult level:Easy]  || 

The species Ar, K+ and Ca2+ contain the same number of electrons. In which order do their radii increase?
1.  Ar < K+ < Ca2+
2. Ca2+ < Ar < K+
3. Ca2+ < K+ < Ar

4. K+ < Ar < Ca2+_

:3. Ca2+ < K+ < Ar 

........

NCERT REFERENCE

 Isoelectronic species:The cation with the greater positive charge will have a smaller radius because of the greater attraction of the electrons to the nucleus._

A cation is smaller than its parent atom because it has fewer electrons while its nuclear charge remains the same.__

Noble-gas: Being monoatomic, their (non-bonded radii) values are very large. In fact radii of noble gases should be compared not with the covalent radii but with the van der Waals radii of other elements.

For metals, we define the term “Metallic Radius” which is taken as half the internuclear distance separating the metal cores in the metallic crystal._________________

Sub-Topic:

• 3.7.1 Trends in Physical Properties
• (a) Atomic Radius

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