Hund's rule (arrow method..???) help!?

Question

I am trying to solve how to make a rectangular arrow method of distributing electrons.

Does somebody knows how to.

Maybe tell me how, to make Xenon into arrow method thing.

Thanks! :)

Answer 1

Wow this is my favorite in chemistry I can help you! =)

This is under the Quantum Numbers. I 'll give you the answer first for xenon then explain it after.

Xenon's last energy level is: 5p6

Just draw 3 boxes... Then place 2 arrows per box. Each arrow must have different directions. The one is pointing upward, the other is pointing downward.

Okay discussion time..

How did I do that?

Get the electron configuration of the element let us take Xe as the example.

Xe= [Kr]4d10 5s2 5p6.

Take the last configuration. 5p6. 5 is the principal energy level, p is the orbital and 6 is the number of electrons. Now. Sinceit is 5p6, p implies that there are 3 boxes. So draw 3 boxes. then distribute the 6 electrons in each box. first, draw one arrow per box pointing upward then when all boxes already have an arrow, draw a single arrow again this time pointing downward. (As what describes by the Hund's rule of multiplicity-- I won't talk about that anymore)

here are the number of boxes per orbital:

s= gives you just one box

p= gives you 3 boxes

d= gives you 5 boxes

f= gives you 7 boxes.

There's more in Quantum numbers just post your comment.

Thanks! Im sure with this.

Answer 2

Hund's rule came about when the modelers had to explain WHY electrons stayed unpaired until they had to pair. NOT obvious without doing the math! By convention, the arrows point UP until pairing in the same orbital type begins and the pairing electron is placed pointing down.

Hund's rule is not required in the MCAS model which has ONLY one electron per orbital!

Xe is an inert gas, so put all the orbital in a row according to increase energy and fill each with an UP and DOWN arrow.