* Electronic configuration of Sodium: 1s² 2s² 2p⁶ 3s¹

* n=2 shell: The n=2 shell includes the 2s and 2p sublevels.

* 2s sublevel: It can hold a maximum of 2 electrons.

* 2p sublevel: It can hold a maximum of 6 electrons.

Therefore, the n=2 shell of sodium contains a total of 2 (2s) + 6 (2p) = 8 electrons.