Identify the neutral element represented by this excited-state electron configuration, then write the ground-state electron configuration for that elemen

The atom would have to contain the same amount of electrons in both the ground start and the excited state. If you count up the electrons in that configuration, there are 7 electrons. The atom with 7 electrons is Nitrogen. If you look at the configuration for Nitrogen, it is 2-5. So assuming you know how to write electron configurations out, your answer would be this: 
Nitrogen (N) = 1s2 2s2 2p3 in the ground state. Count those electrons up and you still have 7 electrons. Excited state is when an atom moves to a higher energy level. You'll still have the same number of electrons.

The answer is celsius 

It would be true sodium reacts with water in a violent way