The valence electron configuration of boron is $2\mathrm{p}^1$.

So, $n=2$, and $l=1$. $m_l$ ranges from $-l$ to $l$. Can I say $m_l$ (for the specified electron) may be (-1 or 0 or +1) or should I just say (-1)?

As you know the $\mathrm{p}$ subshell has three orbitals ($\mathrm{p}_x, \mathrm{p}_y, \mathrm{p}_z$).

Can I associate $\mathrm{p}_x$ with $m_l = -1$, $\mathrm{p}_y$ with $m_l = 0$ and $\mathrm{p}_z$ with $m_l = +1$? (associate each magnetic quantum number with a particular orbital)

I tried to explain what I meant in the following illustration :

$m_s$ is either $+\frac{1}{2}$ or $-\frac{1}{2}$. Can I say $m_s$ (for the specified electron) equals ($+\frac{1}{2}$ or $-\frac{1}{2}$)? (both values) or $+\frac{1}{2}$ because it's alone in the orbital (not paired)

  • $\begingroup$ Part of your question (regarding the assignment of $m_l$ to p orbitals) is answered here: chemistry.stackexchange.com/questions/33645 $\endgroup$ Oct 27, 2015 at 18:59
  • $\begingroup$ For the other part, at this level, I believe all you need to know is that the three p orbitals are degenerate, as well as the two spin states of the electrons. Therefore, regardless of which p orbital the electron is in, and regardless of whether the spin is +1/2 or -1/2, the energy is the same. As such, you would save yourself lots of time if you just wrote one quantum number instead of all the possible quantum numbers, since they all have the same energy. Of course, it's not that simple. There is something called spin-orbit coupling, which changes the energy levels slightly. $\endgroup$ Oct 27, 2015 at 19:02
  • $\begingroup$ Please visit this page, this page and this ‎one on how to format your posts better.‎ Alternatively, visit this chatroom for further formatting guidance. $\endgroup$
    – M.A.R.
    Oct 27, 2015 at 19:13
  • $\begingroup$ I am under no obligation to answer your question in the comments section. Nevertheless, if you want to point something out, you might wish to tell me exactly which part I did not answer. $\endgroup$ Oct 29, 2015 at 13:35
  • $\begingroup$ @orthocresol Actually, you didn't answer my question which is: What's the ml and the ms for the first electron in a p subshell? In other words: What's the ml and the ms for 2p1? If it an exam question what's your answer will be? Sorry, I'm new here I'm editing my comment many times. $\endgroup$
    – user22360
    Oct 29, 2015 at 13:45


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