Question

Of the following electron configurations of neutral atoms, which represents an atom in an excited state?

A
1s2 2s 2 2p 5
B
1s2 2s 2 2p 5 3s 2
C
1s2 2s 2 2p 6 3s 1
D
1s2 2s 2 2p 6 3s 2 3p 2
E
1s2 2s 2 2p 6 3s 2 3p 5

Answer 1

Ground state is 1s2 2s2 2p6 3s2 3p6

An excited state will have a lower level not filled. For example, 1s2 2s1 2p6 would be an excited state. The ground state would be 1s2 2s2 2p5.
That should help you answer the question.