Answer:
Cl[tex]_3[/tex]Al
Explanation:
* = electron
Cl (17) * * * * * * *
Al (13) * * *
If one of aluminum's electrons were added to chlorine to make a full shell, still have 2 left over. So you need another:
Cl * * * * * * * * (full)
Cl * * * * * * *
Al * *
Still have another left over. Aluminum needs to lose another one of its valence electrons to be able to have a full shell. So you take another chlorine:
Cl * * * * * * * * (full)
Cl * * * * * * * * (full)
Cl * * * * * * *
Al *
You will eventuate with 3Cl and 1Al, or Cl[tex]_3[/tex]Al. Modeled above:
