atoms definitions and I hope this helps
Aluminum has an atomic number of 13. The electronic configuration of Al is 1s2 2s2 2p6 3s2 3p1. Al3+ has only 10 electrons so the configuration of Al 3+ is 1s2<span> 2s</span>2<span> 2p</span><span>6. The highest energy level is 2 so the number of electrons in the highest level is the valence electrons which is 8.</span>