Physics 2000 Science Trek Elements as Atoms

A Chemists' Perspective on the Periodic Table

All right, I think I understand now why the periodic table is laid out the way it is. The rows go with the primary energy levels...

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...and there are different sections of the table that go with the different sublevels.

That's right; you can think of the table as being divided into "blocks" like this:

s s
s s p p p p p p
s s p p p p p p
s s d d d d d d d d d d p p p p p p
s s d d d d d d d d d d p p p p p p
s s d d d d d d d d d d p p p p p p
s s
f f f f f f f f f f f f f f
f f f f f f f f f f f f f f

That makes so much sense! Now I can see why someone had the idea of putting the elements in a table like this; once you know how the electron configurations work, this arrangement wouldn't be so hard to come up with.

Actually, the first designer of the periodic table knew nothing about energy levels or even electrons; at the time, hardly anything was known about the structure of atoms.

Really? Then how would anyone know which elements to put where?

Well, that's quite an interesting story. You see, there's more to the periodic table than just electron configurations. Up until now I've been giving you a physicist's view--from the bottom up, so to speak. Now we'll look at the periodic table from a chemist's perspective, from the top down.



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