In this video we take a look at exception type 2's that we have. We're going to say additional exceptions to the electron configuration are observed in. 5 or row five of the periodic table, and a memory tool to help us recall which one they are is 5/8 the number 8B. So if we take a look here, we're dealing with five S group 5B and eight, eight, so 8B.
So looking at these four elements in particular, now we're going to say all are going to have one electron in their 5S orbital. But notice that Palladium is in a different color. That's because Palladium is different from the other three, so it has its own exception on top of the others. For Palladium, we're going to say Palladium has zero electrons in its 5S orbital.
Now if we take a look here, we're going to say that for these elements in particular, the 5S orbital electron or electron is are promoted to a 4D orbital. NB here is niobium. Its atomic number is 41. Its initial electron configuration looks like it would be Krypton 5 S 24 3, but again it's one of the ones in blue and they must have one electron in their S orbital.
So that would mean that we promote this electron to our D orbital. So the new electron configuration would actually be 51 44. Filling U our electron orbital diagram we'd have one electron in the 5S orbital and then following hunts rule we'd half fill to put in our four electrons that are in our 4D orbitals. So this would represent the real electron configuration of niobium. So just remember these are exceptions to for these particular transition metals.