Which among the following electronic configurations belong to main group elements?

A. [Ne]3s¹

B. [Ar]3d³ 4s²

C. [Kr]4d¹⁰5s²5p⁵

D. [Ar]3d¹⁰4s¹

E. [Rn]5f⁰6d²7s²

Choose the correct answer from the options given below:

Solution:

Main group elements are those elements that belong to the s-block and p-block of the periodic table. Let's analyze each given electronic configuration:

A. [Ne]3s¹: This configuration indicates that the outermost electron is in the 3s orbital. Elements with their last electron entering an s-orbital are s-block elements. Thus, this is a main group element (Sodium, Na).

B. [Ar]3d³ 4s²: This configuration indicates that the last electron enters a d-orbital (specifically, the 3d orbital). Elements with their last electron entering a d-orbital are d-block elements, also known as transition elements. These are not main group elements. (This is Vanadium, V).

C. [Kr]4d¹⁰5s²5p⁵: This configuration indicates that the outermost electrons are in the 5s and 5p orbitals, with the 4d subshell being completely filled. Elements with their last electron entering a p-orbital are p-block elements. Thus, this is a main group element (Iodine, I).

D. [Ar]3d¹⁰4s¹: This configuration indicates that the last electron enters a d-orbital (specifically, the 3d orbital, due to the stability of a completely filled d-subshell). This is a d-block element (Copper, Cu), hence not a main group element.

E. [Rn]5f⁰6d²7s²: This configuration indicates that the last electron enters a d-orbital (specifically, the 6d orbital). The 5f⁰ indicates that it's not an f-block element. This is a d-block element, hence not a main group element.

Based on the analysis, only configurations A and C belong to main group elements.