Question

Write an electron configuration for an atom of aluminum-27 in an excited state

Answer 1

Ground state of Al  is 1s²2s²2p⁶3s²3p¹.
Exited state of Al is 1s²2s²2p⁶3s¹3p².

Answer 2

Answer: $1s^22s^22p^63s^13p^2$.

Explanation:

Electronic configuration is defined as the distribution of electrons in the energy levels around an atomic nucleus.

Atomic number helps in determining the electronic distribution  of an atom. We write electronic configuration according to Aufbau's principle in which shells are arranged in increasing energy levels.

Aluminium (Al) is a p block element and its atomic number is 13.

Electronic configuration of aluminium is $1s^22s^22p^63s^23p^1$.

Excite state is achieved when the electron moves to a higher energy level.The 3s electron moves to 3p orbital so that it can form three bonds.

Thus Electronic configuration of aluminium in an excited state is $1s^22s^22p^63s^13p^2$.