Which statement about the first electron shell is true?

The first electron shell, also known as the K-shell, is indeed defined by its capacity to hold a maximum of two electrons. This limitation arises from the shell's proximity to the nucleus and the principles of quantum mechanics. Specifically, the first shell consists of a single s sublevel, which can accommodate two electrons with opposite spins, in accordance with the Pauli exclusion principle.

Understanding the structure of electron shells is fundamental in chemistry, as it explains the arrangement of electrons in an atom and influences chemical bonding and reactivity. In contrast, higher electron shells can hold more electrons because they possess additional sublevels (like p, d, and f). Thus, statements regarding the first shell's capacity to accommodate six, eight, or no electrons do not align with the established principles of atomic structure.