1s² 2s² 2p³

Here's how to understand this:

* 1s²: The first energy level (n=1) has one subshell (s) which can hold up to 2 electrons.

* 2s²: The second energy level (n=2) has a 2s subshell, also holding up to 2 electrons.

* 2p³: The second energy level also has a 2p subshell, which can hold up to 6 electrons. Nitrogen has 3 electrons in its 2p subshell.

Remember: The superscripts indicate the number of electrons in each subshell.