Chapter 5, Problem 5STP

Interpretation Introduction

Interpretation: The correct option for the third energy level of an atom needs to be determined.

Concept Introduction:

Orbital is defined as a mathematical function to explain the wave nature of an electron. Atomic orbitals are present in space around the nucleus of an atom. The most common atomic orbitals are s , p , d, and f .

Answer to Problem 5STP

The correct option is (D).

Explanation of Solution

Reason for correct option:

The principal quantum number 3 has three energy sublevels that are s , p, and d . Now, the maximum number of electrons held by s, p, and d sublevels are 2, 6, and 10 respectively. Thus, the total number of maximum electrons present in the third energy sublevel is 18.

Therefore, option (D) is correct.

Conclusion

Reason for incorrect option:

In the third energy level or energy level with principal quantum number 3, the value of azimuthal quantum number is $l=0,1,\mathrm{2....}n-1$ ; thus, it is 0, 1, 2. Thus, 3 energy sublevels are s , p, and d . Therefore, option (A) is incorrect.

Since there are only 3 energy sublevels that are s , p, and d , there is no f orbital. Therefore, option (B) is also incorrect.

In the third level, there is only 1 s orbital which is 3s . More s orbitals are in first and second energy levels. Therefore, option (C) is incorrect.