What is wrong with the following electron configurations?
a. Ni 1...

Question

What is wrong with the following electron configurations?
a. Ni 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10
b. N 1s^2 2p^5
c. Si 1s^2 2s^2 2p 
d. Mg 1s^2 2s^2 2p^6 3s

Accepted Answer

Welcome back, everyone identify the rule violated by the following electron configurations. For one lithium, two oxygen and three phosphorus, we have choices A through D which outline the different variations of rules. Either the alpha principle hunts rule or poly exclusion principle that are violated by the given configurations of the atoms. So we're going to begin by outlining what each principal or rule outlines. Beginning with the alpha principle recall that it describes that electrons occupy orbitals in increasing energy border. Second, we would outline huns rule and recall that huns rule outlines that electrons fill degenerate orbitals first singly before Dudley and by degenerate, what I mean is energy or sorry orbitals with the same energy level. So for example, if we've got the three P level orbitals, which recall consist of a total of three orbitals, which I'm representing as boxes, recall that the P subs shell can hold a maximum of six electrons. And if we were to fill in a total of four electrons, we would fill them in as single arrowheads in each orbital first. So three single arrowheads in each single orbital first before adding our fourth electron in an opposite spin direction in that first orbital to doubly fill, fill the arrows in. So now we have an upward and downward spin representing two electrons in total. And so, as you observe, we filled in the electrons singly first before doubly pairing them. And in this case, just one of the orbitals were doubly paired. So that is hunts rule. And third, we're going to describe the poly exclusion principle in which we should recall that two electrons in the same orbital should have opposite spins. So an upward arrow spin and a downward arrow spin. So moving forward to the configurations given first for lithium, we're given one s 22 P one. So what went wrong in this configuration is that we go from the one S two orbital to then the second energy energy level of the P subs shell because we have two P next. And that totally skips we can say we skip the two S orbital. And because we know that electrons should occupy orbitals in increasing energy order, we should fill the two S orbital before filling the two P orbital. So configuration one for lithium is a violation of the alpha principle. And based on the answer choices, we have choice A which states that for configuration one, the alpha principle is violated. And that is correct so far. But choice B states that the poly exclusion principle is violated. So we would rule out choice B for that reason since we know that only the Alph bou principle is being violated. And we can also rule out choice C for the same reason because it lists that the configuration for lithium is violating Hun's rule, which is also not applicable. And so that leaves us between choices A and D where choice D also lists for the configuration of lithium that the alpha principle is violated. And we would agree with that. So now let's consider the configuration for oxygen. Given an example, two, we are given a shorthand noble gas configuration where we have helium in brackets since it precedes oxygen on the periodic table. So we have helium in brackets and then it's followed by two S 22 P four. And we know that it's two P four because we are given the orbitals of the two P subs shell, which consist of three total orbitals of these lines filled in with single arrowheads. Now, what we should observe is that the arrowheads in one of the three orbitals for the two P subs shell are filled in with the same direction arrowheads. So the electrons are not filled with opposite spins in the single orbital shown in the two piece subs shell here out of the three. And so we would want to correct that by changing that electron to a downward spin to show opposite spins in the two piece subs shell. And so what is being violated in the configuration of oxygen given is going to be our poly exclusion principle, we should not have electrons with identical arrowhead spins, they should have opposite spins. So going to our answer choices, choice A also lists correctly that the poly exclusion principle is being violated, which we agree for the configuration of oxygen given. And then choice D which we are comparing choice A two says that for the configuration of oxygen hans rule is being violated, which does not align with what we observed. And so we would so far disagree with choice D but let's keep pairing and compare choice three, which is the or rather example, three, which is the configuration of phosphorus. We are given a shorthand noble gas configuration where we have the noble gas that precedes phosphorus on the periodic table, which is neon. So neon is in brackets, followed by the three S two subs shell. And then we have the three P subs shell with a total of three electrons based on its three total orbitals. Now, what we should observe is that out of the 33 P orbitals, the first orbital is filled in doubly, the second orbital is filled in singly and the third orbital is empty. This is a complete violation of what we outlined for hunt's rule which as we stated states that electrons fill same level energy orbitals or degenerate orbitals singly before doubly. And so we would correct the configuration for phosphorus so that we have three P three with each of the electrons filled in singly with the same spin. And so we would want to remove that first or that second electron in the first orbital of the three P subs shell. And that means that for answer choice A because it lists that for the configuration of phosphorus, in example, three hu's rule is violated. We would also agree with that based on what we determined. Choice D lists that the poly exclusion principle is violated. And that does not align with what we determined. So that means we would rule out choice D and that leaves us with choice A as the best answer, choice as the rules violated for the given electron configurations. I hope that this made sense and let us know if you have any questions.

What is wrong with the following electron configurations? a. Ni 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 b. N 1s^2 2p^5 c. Si 1s^2 2s^2 2p d. Mg 1s^2 2s^2 2p^6 3s

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