Final answer:
The correct noble-gas notation for the electron configuration of an atom of chlorine is [Ne]3s² 3p⁵, where [Ne] indicates the electron configuration up to the noble gas neon, followed by 3s² and 3p⁵ for the remaining electrons.
Step-by-step explanation:
The correct noble-gas notation for the electron configuration of an atom of chlorine is [Ne]3s² 3p⁵. Chlorine has an atomic number of 17, meaning it has 17 electrons. In its electron configuration, the first 10 electrons occupy the same energy levels as the noble gas neon (Ne), which can be represented as [Ne]. The remaining 7 electrons fill the 3s and 3p orbitals. Therefore, the 3s subshell contains 2 electrons (3s²) and the 3p subshell contains 5 electrons (3p⁵).
The noble-gas notation is a shorthand method to express electron configurations by starting with the closest noble gas with fewer electrons than the element of interest, and then writing the configuration of the remaining electrons. This notation highlights the valence electrons which are important in chemical bonding. In the case of chlorine, using neon as the reference noble gas simplifies the full electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁵ to the more manageable [Ne]3s² 3p⁵.