What is the maximum number of electrons that can occupy the K shell?

The K shell, which is the first energy level in an atom, can hold a maximum of two electrons. This limitation is derived from the principles of quantum mechanics, particularly the Pauli exclusion principle, which states that no two electrons can have the same set of quantum numbers.

In the case of the K shell, it can only accommodate electrons in its single subshell (the 1s subshell). The maximum electron capacity for any shell is given by the formula 2n², where "n" is the principal quantum number, indicating the shell level. For the K shell, n equals 1, which leads to a maximum of 2(1)² = 2 electrons.

This is why the answer indicating that the K shell can hold a maximum of 2 electrons is correct. The other options, which suggest higher numbers of electrons, pertain to the L shell (which can hold a maximum of 8 electrons), the M shell (max of 18), and the N shell (max of 32), but concerning the K shell specifically, only the capacity of 2 electrons applies.