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Lithuim t1_j5komfz wrote

The heavier noble gases do have a full d-shell as well.

You can fill four successive s orbitals before a d-shell configuration becomes energetically favorable, so there is no d-shell for Helium, Neon, and Argon.

Krypton has a filled d-orbital. Helium only has a full 1s, no p or d.

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321ECRAB123 OP t1_j5kp7hq wrote

But isnt the dshell part of the valence shell of that energy level? I know you skip to the s sublevel of the next level before going back to d. Does this mean the level is not a part of the valence shell for that particular level?

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Lithuim t1_j5kqas7 wrote

There is no 1p, 1d, or 2d structure. These atoms are too small and compact to support the more complex and diffuse electron configurations required to stuff dozens of them into the same space.

The 3d does exist, but it’s higher energy than the 3p and 4s and so doesn’t fill in until later.

Eventually you’ll fill an f-orbital too.

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321ECRAB123 OP t1_j5ksu0e wrote

I know this, im just wondering if d is a part of the valence shell of that energy level. People say that noble gases have full valence shells but us ut really full if d sublevel is skipped?

For the 3rd level the noble gas only full s and p levels, skipping d sublevel so the valence shell is not truely full for noble gases past argon right?

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Lithuim t1_j5kualk wrote

“Valence” refers to the highest level of orbital(s) where electrons relatively freely wander between structures with similar energy levels. How many electrons this is will vary with atomic size.

1s is the lowest orbital, and has no friends - so helium’s valence shell is just two electrons.

Then there’s a big jump.

2s is similar in energy to 2p, and so electrons will move between the two. To fill this next valence layer you need eight electrons.

Then there’s a big jump

3s is similar to 3p, again giving you an 8-valence level.

Then there’s a big jump.

4s is where you’re now at energy levels high enough to generate a d-orbital, and 4s, 3d, and 4p form all sorts of wacky structures. This layer has 18 in the valence level.

Then… you guessed it… there’s a big jump.

“Full valence” is where these big jumps occur. Adding or subtracting an electron from a full structure is relatively difficult. You’re either forming an entirely new structure on top of the existing one or destabilizing a fully spin-paired configuration. Both are difficult, and so atoms and ions with full valence are highly chemically stable.

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breckenridgeback t1_j5ktnyp wrote

> I know this, im just wondering if d is a part of the valence shell of that energy level.

The 3d shell is on the same level as the 3s and 3p orbitals in a hydrogen atom, but in the larger atoms that actually fill the 3d shell in their ground state, it turns out that the 3d shell ends up much higher-energy than the 3s and 3p shells because of how it interacts with other electrons. It ends up with an energy between the 4s and 4p orbitals instead, so for the purposes of the periodic table, you can think of 3d as hanging out in the fourth "shell" instead.

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ScienceIsSexy420 t1_j5l2z5v wrote

Which is why the transition metals start in the fourth period, but utilize the 3d orbital

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