Copper's ground state electron configuration is [Ar] 3d¹⁰ 4s¹. However, when copper is excited, an electron can be promoted to a higher energy level. Here are some possibilities:

* 4s¹ → 4p¹: This is the most likely excited state, as the 4p orbital is the next highest energy level after the 4s. The electron configuration becomes [Ar] 3d¹⁰ 4p¹.

* 4s¹ → 5s¹: While less likely, an electron could also be excited to the 5s orbital, resulting in the configuration [Ar] 3d¹⁰ 5s¹.

* 4s¹ → 4d¹: Excitation to the 4d orbital is possible but less likely because the 4d orbital has higher energy than the 4p. This would result in [Ar] 3d¹⁰ 4d¹.

It's important to note that there are many possible excited states, depending on the amount of energy absorbed by the copper atom.

However, it's not possible to give a single "electron configuration of copper at excited state" because there are multiple possibilities.