The following question arises from a set of statements from which I'm asked to state whether they are true or false.

This is as follows:

Indicate which of the following statements are true or false

  1. On $\underset{np}{\underline{\uparrow}\,\underline{\uparrow}\,\underline{\downarrow}}$ there is a transgression to Hund's rule of maximum multiplicity

  2. The given box notation $\underset{np}{\underline{\uparrow\,\uparrow}}$ is a transgression to Pauli's exclusion principle.

  3. The following configuration $1s^22s^22p^13s^1$ is a transgression to Pauli's exclusion principle.

  4. The electron configuration of Silver $(Z=47)$ is $[Kr]5s^{1}4d^{10}$.

  5. Two chemical species with the same number of electrons not necessarily have the same configuration.

Given these statements I found it difficult to make a proper interpretation of what was intended with the fifth and the first option.

The second option is true. As two electrons occupying the same orbital cannot have the same quantum numbers.

The third option is not true due that's not a transgression to Pauli's exclussion principle. But rather to Aufbau's build up principle. Because it states that the electrons will occupy the orbital with the lowest energy possible.

The fourth option is correct, that's the electron configuration of Silver.

But the problem arises from the first option as I don't know if it does make a transgression to Hund's principle of maximum multiplicity?. As I understand there isn't any reason to justify that the electron will always have to be filled with a $m_s=-\frac{1}{2}$. It only states that the most stable configuration will be the one where electrons fill the most orbitals as possible.

Then the fifth option is a bit hard to understand, as I don't get very clear what's the meaning of chemical species. I'm assuming since this question is related with atomic structure chapter, it is referring to atoms. In the given context ions more specifically, and understood in such way it does say that two isoelectronic atoms will not have the same configuration. But is that possible?. How can it be justified?.

  • $\begingroup$ If $S$ is total spin the multiplicity is $2S+1$ so in (1) it is $2(1/2)+1$ but it could be $2(3/2)+1$ if the spins were all parallel. In (4) you could change configuration in the C atom of Q3 to be ..$2s^1...3s^2$ with same number of electrons. $\endgroup$ – porphyrin Feb 22 at 8:26
  • $\begingroup$ 5th option let me think of ions and molecules. It shouldn't be there if the course has covered just atoms. You should ask the author :(( $\endgroup$ – Alchimista Feb 22 at 9:15
  • $\begingroup$ @porphyrin I don't think what it was intended was to change the configuration but rather give a judgement solely on what was written, in that sense I assumed that with no allowed modification of the configuration, it is a transgression to Aufbau's rule but not Pauli's rule. Regarding the total spin multiplicy where did you get $\frac{3}{2}$ for the value of $S$?. $\endgroup$ – Chris Steinbeck Bell Feb 25 at 11:18
  • $\begingroup$ 3/2 three electrons each with spin ms =+1/2 $\endgroup$ – porphyrin Feb 25 at 16:14

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