Question

Which of the following options correctly represents the order in which electrons are filled in the s and d subshells of the first three elements in Group 11 (or 1B)?

A) 4s, 3d, 4p
B) 3s, 3p, 4s
C) 4s, 4p, 3d
D) 3s, 3d, 4p

Answer 1

The correct order for electron filling in the s and d subshells for Group 11 elements is 4s before 3d, corresponding to Option A) 4s, 3d, 4p.

Step-by-step explanation:

The correct order in which electrons are filled in the s and d subshells for the first three elements in Group 11 (or 1B) is 4s before 3d. Therefore, Option A) 4s, 3d, 4p is the correct sequence for electron filling in these elements. The periodic table's structure reflects this order; after filling the 4s subshell, electrons fill the 3d subshell. This trend is observed due to the energy levels of the electronic orbitals where the 4s has a lower energy level compared to the 3d subshell at this point in the periodic table.