periodic table(元素周期表)2

Haha, I feel a bit sorry for telling you the wrong stuff. very sorry..
Also I think I should redefine what does group number means. Group number define how many electrons they give or take in a reaction.
Groups 1 give 1
Groups 2 give 2
Groups 3 give 3
Groups 4 give or take 4
Groups 5 take 3
Groups 6 take 2
Groups 7 take 1
Groups 8 give 0
(The previous definition states: Group number is the number of electrons in outer-most shell, that is not wrong, but when it is comes to explaining more complex atoms like transition metals, then this definition don't really work.)

Q1: Let's talk about Group1 a / b
For a group 1A atom, For example:
Potassium (Same period as Cu la..) It's electron configuration is [Ar] 4s1. So when it reacts, it gives out 1 electron. DIRECTLY from 4s orbital.

For a group 1B atom, for example:
Copper (Same period as K) It's electron configuration is [Ar] 4s2 3d9, now, the 3d orbital will take one electron from 4s orbital. And leaving the 4s orbital half filled. which make the both 3d and 4s orbital stable.When react, the atom donate 1 electron form the SAME 4s orbital but you can see that they give electrons out in a different way.

So group A/B is used to distinguish how it gives electrons..

VERY VERY sorry that I told you the wrong thing...

Question 2: Yes Yes Yes you are right, i forgot to tell you about this.. When it comes to group 8B , the "Group theory" starts to fail and brings confusion from the old IUPAC and CAS system (the roman numbers). So, the IUPAC have developed a new scheme of naming the groups. You can take a look at the wikipedia website at the reference section. This result in a new kind of periodic table like this one, with new groups.

http://www.dayah.com/periodic/

see the row of number (1-18) on the top.

Please don't misunderstand me to make you post another question so I can get extra points, i just don't want to break the rules of yahoo answers. (I should not answer your question when it is outside of yahoo knowledge+ .)

2007-12-17 10:17:02 補充：
the difference between A and B is the A give electron DIRECTLY from 4S orbital and B gives electrons by REARRANGE first then GIVE electrons. If you still don't understand, you can email me.. [email protected]