(a) For an He+ ion, do the 2s and 2p orbitals have the same energy? If not, which orbital has a lower energy?

Video transcript

hi everyone for this problem it reads for a lithium ion which one between the three S and the three P orbital has the lower energy. Okay. So in order to answer this problem, we're going to need to know number of electrons and we can start off with a neutral lithium ion. Okay. A neutral lithium ion. We can know how many electrons it has by looking at its atomic number. Okay. So the atomic number is what we can look at on the periodic table and its atomic number is going to be equal to the number of electrons and protons. The number is equal when the when it's neutral. So the atomic number for lithium is three. So that means a neutral lithium atom has three electrons. Okay. And we'll all right here neutral. However, a lithium cat ion in this case we have a plus two charge. What this means is it is missing two electrons. So if our neutral lithium ion adam has three electrons and this lithium ion has two of those missing. That means our lithium ion Has only one electron. Okay with this, we'll need to know that when you're dealing with a one electron particle, the energy of an orbital depends only on the value of N. And N. Is our period. Okay, so looking at three S and three P. When we only have one electron particle, the energy only depends on the period. So the period for both of these is three. Okay, so N equals three. So what that means is they have the same energy, they have the same energy because they're on they're in the same period. And because it's only one electron, the energy of the orbital depends only on the value of N, which is the period. That's it for this problem, I hope this was helpful.