Consider the following electron configurations to answer the question.

(i)   1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹

(ii)   1s²2s²2p⁶3s²3p⁵

(iii)   1s²2s²2p⁶3s²3p⁶4s²3d⁸

(iv)   1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

(v)   1s²2s²2p⁴3s¹

An example of an excited state (higher energy level than the ground state) is ________.