Question

Which of the following has pseudo-inert gas configuration in the (n-1) shell?
A.Typical transition elements
B.Zinc group elements
C.Both of the above
D.None of the above

Answer 1

Hint: To answer this question, we must understand what is meant by pseudo inert gas configuration. We know that inert gases have 8 electrons in their valence shell, so in this question we have to find out which group has 18 electrons in their penultimate shell instead of the usual 8 electrons.

Complete step by step answer:
-We can now understand from the hint provided that elements having filled the orbital, along with completely filled s and p orbitals, are considered to be elements having pseudo inert configuration. This is named pseudo inert configuration because these elements are having 18 electrons in their valence shell instead of having 8 electrons.
Let us now look at the trends of electronic configuration of the groups provided to us as options:
-Transition metals are defined as those elements which have partially filled d orbitals. The d-block elements are divided into the first transition series containing the elements Sc through Cu, the second transition series from Y to Ag, and the third transition series (the element La and the elements Hf through Au). Actinium, Ac, is the first member of the fourth transition series, also includes Rf through Rg.
-Now, coming to the zinc group, they have 10 electrons in their d subshell which means a completely filled d subshell and thus 18 electrons in (n-1) shell.
Therefore, the elements which have pseudo-inert gas configuration in the (n-1) shell are typical transition elements and Zinc group elements.

Hence, the correct answer is Option (C) Both of the above.

Note: It is imperative to remember that cations with pseudo inert gas configuration or with inert pair configuration generally have greater ENC (Effective Nuclear Charge) than cations with noble gas configuration. This by virtue of their charge distribution and size ratio.