Electron subleveling?

[FearMyChewyWafflez]

Why do some elements have 1 electron on the outer shell while there can be more electrons in the previous shell? For example, all the alkali metals.

[Ophiolite]

Hello Wafflez: the title of this section is Homework Help, not Homework Done for You.

 

If you will show some indication that you have made an effort, tell us what your thinking is so far, I am sure members will be happy to help you.

 

I'll give you this clue - what determines the number of electrons an atom has? How might that relate to your question?

[FearMyChewyWafflez]

Hello Wafflez: the title of this section is Homework Help, not Homework Done for You.

 

If you will show some indication that you have made an effort, tell us what your thinking is so far, I am sure members will be happy to help you.

 

I'll give you this clue - what determines the number of electrons an atom has? How might that relate to your question?

Well then I shouldn't of posted in here, because this isn't for homework, just personal curiosity. The number of protons determines the amount of electrons, since atoms charges are neutral, something has to even out the positive charge of the protons. I have no idea why that might relate to my question.

[Ophiolite]

The number of electrons that can fill a shell is limited. The first shell can hold no more than two electrons, so once we get to helium we have a full shell. The next element is sodium, with atomic number three. So it has three protons and three electrons. The third electron cannot go into the first shell which is full, so it goes into the next one. One electron in the outer shell, two in the inner shell.

 

As atomic number increases we wind up with atomic number 10: two electrons in the inner shell and eight in the outer shell - this is neon. That shell is now full, so when we move to atomic number 11 the next electron must go into the next shell. That gives us the element sodium, which as you can see must therefore have three shells with 2 electrons in the inner shell, 8 in the next and one in the last.

 

Make sense?

[FearMyChewyWafflez]

The number of electrons that can fill a shell is limited. The first shell can hold no more than two electrons, so once we get to helium we have a full shell. The next element is sodium, with atomic number three. So it has three protons and three electrons. The third electron cannot go into the first shell which is full, so it goes into the next one. One electron in the outer shell, two in the inner shell.

 

As atomic number increases we wind up with atomic number 10: two electrons in the inner shell and eight in the outer shell - this is neon. That shell is now full, so when we move to atomic number 11 the next electron must go into the next shell. That gives us the element sodium, which as you can see must therefore have three shells with 2 electrons in the inner shell, 8 in the next and one in the last.

 

Make sense?

Yes, and i knew this, but the element cesium goes 2, 8, 18, 18, 8, 1. while the total number of electron in each shell goes 2, 8, 18, 32, 50, 72. And sodiums atomic number is 11, lithium is 3.

 

Again, my question is why are there electron ins in the outer shell while there can be more in the previous shell (cesium, for example)

 

PS. You said that sodium's atomic number 3 at first, which is not true, its 11. but then you said that sodiums atomic number is 11. Did you mean lithium for atomic number 3?

Edited December 14, 2012 by FearMyChewyWafflez