 Okay, so let's try this one, and it's exactly like the last problem that we did, except this one has a charge where the last one didn't, okay. Remember, aluminum's normal charge is going to be plus 3 because it likes to lose those three electrons. Okay, so for the following symbol, we give the atomic number, mass number, the number of protons, the number of neutrons, the number of electrons, the number of valence electrons and the number of inter-electrons. So the atomic number again is going to be 13, you get that from the periodic table. The mass number is 28, it's given to you in the problem. The number of protons is also 13. To be an aluminum atom, you have to have 13 protons. That's what it means to be an aluminum atom. The number of neutrons is going to be the mass number minus the number of protons. So it's going to be 15, the number of electrons. Well, in this case, it's got a charge, okay. So we've got to look for the charge to make sure we've got the right amount of number of electrons, okay. So for a neutral atom, the number of electrons would be equal to the number of protons, which would be 13, okay. But in this case, we've got plus 3 as our charge, okay. So we're wondering what is 13 minus what equals 3. So what is this? 10, right. So x equals 10, right. So the number of electrons must be 10. In this case, the valence electrons are kind of ambiguous, okay. So I would say that the valence electrons is 0 because you're a period 3 element and you've taken away all those electrons. You could alternatively say you have 8 valence electrons, okay. Either way is fine. I would give you credit for either one. The inner electrons is 10 electrons, okay. Because of course, you count all the other electrons and say 10. You could alternatively potentially say 2 here and I would give you credit, okay. Why? Right? Yeah.