Guidance with some chemistry concepts

[Ritzycat]

Hello! I understand that a lot of this may be considered physics, but It is for AP Chemistry.

We will likely be required to identify a certain element on the periodic table given a set of quantum numbers of one of its electrons. I understand the primary quantum number, n, essentially corresponds to the rows on the table. L dictates the type of orbital (s, p, d, etc.). But I am confused on how I can further narrow it down using magnetic quantum number (m) and spin number.

For example, I know n=2, l=0 would be either Lithium or Beryllium. What would be the m / spin numbers for each? Essentially, we are being asked to pinpoint a certain element on the table given 4 quantum numbers. I understand how to narrow it down using the primary quantum number and angular quantum number but do not understand how I can further narrow it down using magnetic quantum number and spin number.

Sorry if that question is a little discombobulated, hopefully it makes sense.

My other concern is the uncertainty principle. How are we meant to do calculations using the uncertainty principle?

 

[Bystander]

Tain't too "discombobulated" to understand your concern. You will have to be given additional information about the electron for which quantum numbers are given, whether the atom is in its ground state, and possibly more; for instance, "n=2, l=0" covers everything from excited H (or He) through the transuranics. Presumably you'll be told it's the highest energy electron in a ground state atom, and judging from your presentation of the question you won't have much trouble. Transition metals and lanthanides might get a little weird depending on how much cribbing material you're allowed.

Uncertainty? What sort of calculations are you being asked/expected to handle?

 

[Ritzycat]

Yes - I think that's correct. We are going to be expected to pinpoint the highest energy electron in the ground state atom, and we'll have to identify what element that would be based on a set of 4 numbers. However, I'm not sure how I can use the 3rd and 4th numbers to identify what element we are talking about.

As for uncertainty, the "delta" for each X and MV mean uncertainty, not change, like delta normally means, correct? I don't actually need the value for mass or velocity itself to solve for the other, only its uncertainty?

 

[Bystander]

If you're given a set of quantum numbers, you have been given the order in which the quantum levels are filled, have you not, and can then count electrons.

"Δ" indicates uncertainty, yes, and those uncertainties are the values you use.

 

[DeeNos]

Hello! It's great to see your interest and understanding of the concepts in AP Chemistry. Let's start by discussing the quantum numbers and how they relate to the periodic table. As you mentioned, the primary quantum number, n, corresponds to the rows on the table, also known as the energy levels. The angular quantum number, l, dictates the type of orbital, with s orbitals having l=0, p orbitals having l=1, and so on.

The magnetic quantum number, m, further specifies the orientation of the orbital within a sublevel. For example, for l=1 (p orbitals), m can have values of -1, 0, or 1, corresponding to the three different p orbitals (px, py, pz). So, for n=2 and l=0, there is only one possible orbital, the s orbital, and therefore, m=0.

The spin number, represented by the letter s, describes the spin of an electron within an orbital. It can have a value of +1/2 or -1/2.

To pinpoint a certain element on the periodic table using these quantum numbers, you would need to know the specific electron configuration of that element. This would tell you the values of n, l, m, and s for each electron in that element's atom. For example, Lithium has an electron configuration of 1s^2 2s^1, so the electron in the 2s orbital would have the quantum numbers n=2, l=0, m=0, and s=+1/2.

As for your question about the uncertainty principle, this principle states that it is impossible to know both the exact position and momentum of a particle at the same time. In chemistry, this principle is applied to the position and velocity of an electron. In calculations, we use the uncertainty principle to estimate the range of possible values for these properties. This is important in understanding the behavior of electrons in atoms and molecules.

I hope this helps clarify some of your questions. Keep up the good work in AP Chemistry!