Final answer:
The ground-state electron configuration of a sodium ion (Na+) is [Ne], identical to that of neon, due to the loss of its single 3s valence electron.
Step-by-step explanation:
The question asks for the ground-state electron configuration of a sodium ion (Na+). The electron configuration of a neutral sodium atom is [Ne] 3s¹, where [Ne] represents the core electron configuration identical to the noble gas neon with atomic number 10. When the sodium atom loses its single valence electron to become a sodium ion, it achieves a noble gas configuration, leaving it with an electron configuration identical to that of neon, which is [Ne] without the 3s¹ electron.