When it comes to the transition metals, remember that they occupy the D block of the periodic table or the Group B elements of the periodic table. For cations where we're losing electrons, electrons are lost from the highest shell number. First, remember your shell number uses the principal quantum number N. If we take a look here, remember we have our S block, we have our P block, we have our D block, and down here we have our F block.
If we're to take a look at titanium, here goes titanium right here. And we've talked about condensed electron configurations before in earlier chapters. If you don't recall that, make sure you go take a look at our videos on condensed electron configurations. Right now, let's look at titanium. We would say that titanium has an atomic number of 22, which means it has 22 electrons when it's neutral. The last double gas we passed before we get to titanium is argon. So we start out with argon, then we'd say 4S14S2.
So there's two electrons. And remember we show those two electrons in this orbital and according to the Poly exclusion principle, they have to have opposite spins. One spins up, one spins down. Then we'd say that titanium is in our 3D row and it'd be 12. Hun's rule says that electrons that are in the same type of orbitals have same energy or are degenerate. So we have fill first, so we go up up. So if we wanted to translate this into simpler term we just say it's argon 4S23D2. This would be the condensed electron configuration of titanium atoms.
Now here we're looking at titanium 3/3 plus means it's lost three electrons. Remember we take electrons from the highest end value. For us, 4 means that these electrons are in the fourth shell, or N = 4. Here this means N = 3. We have to lose 3 electrons total because the charge is 3 plus. So the first two electrons are lost from our 4S orbitals, so we lose these two electrons. So we have 0 left here, and then we still need to lose one additional electron, and that will come from our 3D, leaving us with one left.
So if we wanted to fill out this electron orbital diagram, we'd still have argon 4S is empty, and then 3D only has one electron left. So here we could say it's argon for A03D1. Or you can write it as Argon 3D one because there's no electrons left in the four orbit, so you can just ignore it, right? So just remember, this is how we'd approach writing the condensed electron configuration of a transition metal atom and its respective cation.
