Chapter 5, Problem 8STP

Interpretation Introduction

Interpretation: The configuration of the highest occupied energy level for the beryllium element needs to be identified.

Concept Introduction: The electronic configuration represents the arrangement of electrons in atomic orbitals. Here, s , p , d, and f are sublevels in which electrons are distributed. The maximum number of electrons in s , p , d, and f orbitals are 2, 6, 10, and 14.

Answer to Problem 8STP

The correct option is (B).

Explanation of Solution

Reason for correct option:

The given element is beryllium. The atomic number of beryllium is 4 thus, there are 4 electrons in a beryllium atom. The increasing order of energy of sublevels is as follows:

  $s<p<d<f$

Thus, the filling of electrons takes place in the order s , p , d, and f .

The electronic configuration can be represented as follows:

  $1s^{2}2s^2$

Thus, the highest occupied energy level is $2s^2$

Therefore, option (C) is correct.

Conclusion

Reason for incorrect options:

The electronic configuration of beryllium is as follows:

  $1s^{2}2s^2$

The increasing order of energy with respect to principal quantum number is as follows:

  $1<2<3<4$

Thus, the highest occupied energy level will be with principal quantum number 2. From the electronic configuration, there is 1 sublevel with this principal quantum number that is $s^2$ .

Therefore, options (A), (B), (D), and (E) are incorrect options.