Electrical Apprenticeship Exemption Practice Exam 2025 – Your All-In-One Guide to Mastering the Exam!

The maximum number of electrons that can exist in an orbit of an atom is determined by the formula 2N², where N represents the principal quantum number, which indicates the energy level or shell of the atom.

In the case of the first orbit (or first energy level), N is equal to 1. When we apply the formula:

2N² = 2(1)² = 2 * 1 = 2

This shows that the first orbit can hold a maximum of 2 electrons. This is consistent with the structure of the atom, where the first shell or energy level is filled with only 2 electrons, corresponding to the first two elements in the periodic table: hydrogen and helium.

The other options do not accurately reflect the capacity of the first orbit. For instance, while the second orbit can accommodate up to 8 electrons, and the third can hold even more, these values do not pertain to the first orbit, which is specifically limited to 2 due to the principles of quantum mechanics that govern electron configuration. Thus, the correct understanding revolves around the specific application of the formula 2N² for the first shell.