How many electrons are in the “3” energy shell? Electrons are counted, so your answer should be a whole number.
The correct answer and explanation is :
The “3” energy shell can hold a total of 18 electrons.
Explanation:
The energy shells of an atom are labeled by quantum numbers, and each shell corresponds to a specific principal quantum number (n). The number of electrons that can occupy a shell is determined by the formula:
[
\text{Maximum electrons in a shell} = 2n^2
]
Where “n” is the principal quantum number representing the energy level or shell.
For the “3” energy shell, the principal quantum number is n = 3.
Now, applying the formula:
[
2n^2 = 2(3)^2 = 2 \times 9 = 18
]
Thus, the third energy shell can hold a maximum of 18 electrons.
Why 18 electrons?
Each energy shell is divided into sublevels, which are labeled as s, p, d, and f. These sublevels contain orbitals, and each orbital can hold a maximum of two electrons. The distribution of electrons in the third shell (n = 3) is as follows:
- 3s sublevel: Can hold a maximum of 2 electrons.
- 3p sublevel: Can hold a maximum of 6 electrons.
- 3d sublevel: Can hold a maximum of 10 electrons.
When you add up all the electrons in these sublevels, you get:
[
2 + 6 + 10 = 18 \text{ electrons}
]
Conclusion:
The “3” energy shell can hold 18 electrons because it contains three sublevels (s, p, d), and each sublevel has a maximum electron capacity of 2, 6, and 10 electrons, respectively. This results in a total of 18 electrons.