The electron configuration notation for Na is:

1s 22s 22p 6

1s 22s 22p 5

1s 22s 22p 63s 2

1s 22s 2

1s 22s 22p 63s 1

The answer to your question is the last one.

Explanation:

The Electron configuration of Na

Sodium is an Alkali Metal with 11 electrons. This metal is located in group lA, which means that must have only one electron in its outermost shell

1s²2s²2p⁶ This electron configuration has 8 electrons in its outermost shell.

1s²2s²2p⁵ This electron configuration has 7 electrons in its outermost shell

1s²2s²2p⁶3s² This electron configuration has 2 electrons in its outermost shell.

1s²2s² This electron configuration has 2 electrons in its outermost shell.

1s²2s²2p⁶3s¹ This electron configuration has 1 electron in its outermost shell and 11 electron in total, so this is the right answer.