# I need help with some chem questions?

If you can help me answer (and maybe explain a little) any one of the, then that'd be great!

Which set of four quantum numbers is not possible for a 3p electron?

(a) 3, 1, +1, +1/2

(b) 3, 1, 0, +1/2

(c) no correct response (they're all possible sets of quantum numbers for a 3p electron)

According to quantum mechanics, how many subshells are present in the second shell (n=2)

Is it 11? There is 2s2, 2p6, 3d10, 4f14 so it'd be 1+3+5+7 = 16

I tried 16 though and I guess it's not right o.o

What is the maximum number of *electrons* that can occupy the fourth shell (n=4)?

Is it 32??

What is the first d element in the 5th period to which Hund's rule must be applied when writing the orbital diagram? Is it Ru?

How many elements are there in the periodic table whose electron configuration ends in ns2(n-1)d10np2? n=shell number

Is it 28?

### 1 Answer

- 7 years agoFavorite Answer
c. They're all possible. n=3 since 3rd energy level, l=1 since p sublevel, then for ml, the range is [-l, l], which gives you -1, 0, 1. For ms, it's always +/- 1/2.

You're only talking about the second energy level. The second level can only have s and p sublevels, which makes for two subshells. s has one orbital while p has 3, this gives a total of 4 orbitals in the second level.

The formula for the max number of electrons in a given energy level is 2n^2, so, 2(4)^2=32. This is correct.

Hund's rule states that electrons enter singly before being paired. This trend will start with zirconium. Yttrium has a configuration of 5s2 4d1, while Zirconium has a configuration of 5s2 4d2. The second 4d electron in zirconium occupies a different orbital from the first 4d electron.

It's only 4, from germanium downwards. (Group IVA)

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