Help with AS level chemistry question

Ytterbium,Atomic number 70 , is the first element in the periodic table to have the first four shells full.

How many orbitals are there in the third shell of Ytterbium.

Reply 1

username10190205

Original post by ihaveno name

Ytterbium,Atomic number 70 , is the first element in the periodic table to have the first four shells full.

How many orbitals are there in the third shell of Ytterbium.

have you learnt about orbitals and sub shells yet?

Reply 2

ihaveno name

Original post by username10190205

have you learnt about orbitals and sub shells yet?

Yes I just don’t understand how they got the answer as 9

Reply 3

Eimmanuel

Study Forum Helper

Original post by ihaveno name

Yes I just don’t understand how they got the answer as 9

Hope this diagram can help.

Reply 4

Nitrotoluene

Original post by ihaveno name

Ytterbium,Atomic number 70 , is the first element in the periodic table to have the first four shells full.
How many orbitals are there in the third shell of Ytterbium.

I think there may be a slight error in this statement. Ytterbium (Yb) has an atomic number of 70, which means it has 70 electrons. However, it's not the first element to have the first four shells full.

The first four shells (1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f) are full of elements with atomic numbers up to 20 (calcium). Ytterbium has a different electron configuration.
Let's count the orbitals in the third shell of ytterbium:
3s: 2 electrons
3p: 6 electrons
3d: 10 electrons
In total, there are 2 + 6 + 10 = 18 orbitals in the third shell of ytterbium.
Here's a simple demonstration to illustrate this:
Imagine a set of 18 boxes, each representing one orbital in the third shell. You can use different colours to distinguish between the s, p, and d orbitals.

•

Fill the 3S box with 2 electrons (red).

•

Fill the 3p pocket with 6 electrons (blue).

•

Fill the 3d shell with 10 electrons (green).

You now have a visual representation of the 18 orbitals in the third shell of ytterbium.

Kind regards from Italy.

(edited 10 months ago)

Reply 5

UtterlyUseless69

Original post by Nitrotoluene

I think there may be a slight error in this statement. Ytterbium (Yb) has an atomic number of 70, which means it has 70 electrons. However, it's not the first element to have the first four shells full.
The first four shells (1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f) are full of elements with atomic numbers up to 20 (calcium). Ytterbium has a different electron configuration.
Let's count the orbitals in the third shell of ytterbium:
3s: 2 electrons
3p: 6 electrons
3d: 10 electrons
In total, there are 2 + 6 + 10 = 18 orbitals in the third shell of ytterbium.
Here's a simple demonstration to illustrate this:
Imagine a set of 18 boxes, each representing one orbital in the third shell. You can use different colours to distinguish between the s, p, and d orbitals.

•

Fill the 3S box with 2 electrons (red).

•

Fill the 3p pocket with 6 electrons (blue).

•

Fill the 3d shell with 10 electrons (green).

You now have a visual representation of the 18 orbitals in the third shell of ytterbium.
Kind regards from Italy.

This question was asked a good 10 months ago, but your solution (if the question were asking for the number of electrons rather than orbitals are in the third quantum shell) would be nonetheless correct.

If you look up the electrons per shell of Ytterbium and the elements either side of it (Er, Tm and Lu) on Wikipedia, you will see that the fourth quantum shell reaches its capacity of 32 for Yb and Lu, but Tm has 31 electrons in its fourth quantum shell and Er has 30.

The 4f subshell fills awkwardly (part of why the lanthanides and actinides are not studied in depth in any pre-university courses that I am aware of) and even though you may predict Yb to have a single 5d electron, it in fact does not.

This electron instead occupies the 4f subshell, which is likely at least in part due to there being better overall exchange energy stabilisation as a result of adopting this electronic arrangement instead of having a singular 5d electron. As such, I do not believe there is any error in the question.

Edited for clarity

(edited 10 months ago)

Reply 6

unharmed-profess

Original post by ihaveno name

Ytterbium,Atomic number 70 , is the first element in the periodic table to have the first four shells full.
How many orbitals are there in the third shell of Ytterbium.

It's 9 because the third shell contains 3 subshells known as "s" "p" "d" where s has only one orbital which can fit 2 electrons, "p" has three orbitals which holds 6 electrons and the "d" subshell has five orbitals which hold 10 electrons
Therefore one + three+ five= nine orbitals

Hope this helps x