Question about the periodic table of elements

[BigToque]

I know that in the main group elements, 1A-8A all stand for the number of valence electrons.

I assumed that groups 3B-2B (columns 3-12) all stood for the number of valence electrons as well, but were marked with a B to distinguish them from the main group elements.

If that assumption was right, why are columns 8,9, and 10 all listed as 8B, and not 8B, 9B, 10B?

(Sorry about the crappy quality pic)

 

[Brainonska511]

People still use the A/B notation for periods?

 

[FoBoT]

just wanted a better picture, i don't know

 

[spidey07]

Thought it had to do with what shell the electrons were in. Been forever though.

 

[Adrenaline]

Here is the source.

Group 8B (8, 9, 10)
The Group 8B elements are designated Groups 8, 9, and 10 in the IUPAC designation. The elements in each period of these groups are very similar in their chemical and physical properties. The Group 8 elements usually have the electron configuration (n-1)d6 ns2, the Group 9 elements usually have the electron configuration (n-1)d7 ns2, and the Group 10 elements usually have the electron configuration (n-1)d8 ns2.

 

[destrekor]

Transition Metals are a bunch of bitches that just don't belong nor conform to the basics.

I assume they only go up to 8 in reference to the other groups, based on valence electrons.
I don't know what it's called, but the transition metals aren't grouped according to valence electrons, because they play by their own rules. They have different electron configurations that are referenced to determine their attitudes toward potential reactivity.

IIRC, there can only be 8 electrons in the outer shell, at least that is true for what are apparently the A groups. How many are there determines the tendency to react and either form negative or positive ions (or how they bond).

I quickly googled the transition metals and just got mind fucked. Sorry, I refuse to even attempt to understand their categorization, and thus I can be of no further help.
Also, there is a decent-to-strong chance everything else I said is completely wrong. But I tried.