Here it says write the full electron configuration for the nitride ion, so it ends with I'd, which means we're dealing with the anion form of nitrogen. So nitrogens in Group 3A, so its charge is -3 or 3 -. 3 minus means that we have gained 3 electrons, so we'll take that into account when we're doing its electron configuration.
So the steps we're going to do here is we're going to provide the electron configuration for the neutral form of the element. So nitrogen when it's neutral, it has an atomic number of seven. Its full electron configuration is 1S22S22P3. Next Step 2 we're going to add electron or electrons to the orbitals that can accommodate more electrons. So for the nitride ion, here we have this S can only hold up to two electrons Max, SO1S2 and 2S2 stay the way that they are.
Remember, the P sublevel can hold up to six electrons. Right now it only has three. We're gaining three additional electrons, so all of them can be tossed into this 2P6. So this would represent the full electron configuration of the nitride ion. So we can say this as an acceptable answer.
One more thing we can also say is that it now has the same electron configuration as a noble gas, and a noble gas would be neon. So both of these answers are acceptable. You can show the full electron configuration here and you can say that it is the same Electron configuration as Neon. Technically in this answer I'm asking for the full electron configuration, so this would be the best answer, but just keep in mind it now also has the same electron configuration as a noble gas, so if we wanted to do a shorthand or condensed electron configuration you could just write this as an answer.