What is the maximum number of electrons that can be held in the second shell of an atom?

The maximum number of electrons that can be held in the second shell of an atom is 8. This is determined by the formula 2n², where n is the principal quantum number representing the shell level. For the second shell (n=2), you calculate it as follows:

2n² = 2(2)² = 2(4) = 8.

Thus, the second shell can accommodate up to 8 electrons. This capacity is essential in explaining the electron configuration of elements, as the filling of electrons in shells contributes to the chemical properties of an atom. The first shell (n=1) can only hold a maximum of 2 electrons, while subsequent shells can hold even more, but the pertinent limit on the second shell remains 8.