Final answer:
The electron configuration of an aluminum atom is 1s²2s²2p63s²3p¹. Aluminum has three valence electrons in the third energy level, (3s²3p¹). The cation, Al³+, is formed when these three valence electrons are lost, leaving the configuration for the noble gas neon, 1s²2s²2p6.
Step-by-step explanation:
The electron configuration of an aluminum atom is 1s²2s²2p63s²3p¹. Aluminum has three valence electrons in the third energy level, (3s²3p¹). The cation, Al³+, is formed when these three valence electrons are lost, leaving the configuration for the noble gas neon, 1s²2s²2p6.