Can someone please explain me? I have some questions about the Periodic Table...(sorry for any grammar mistake)

In the tranzition metals groups : group 3(IIIB) , group 4(IVB)...,group 7,8and 9(VIII B), group 11 (IB) , group 12(IIB)

Why groups 7,8,9 are all VIIIB?

And what does the "B" represent?

Why does the tranzition metals series start with III B and end with I B and II B?

And why group 13 is still IIIB?

And...in the groups 1,2,14,15,16,17,18 , what does the "A" represent ( I A, IVA , V A, VI A , VII A , VIII A)

1 Answer
Truong-Son N.
Mar 30, 2018

Well, first of all, groups 8, 9, and 10 are VIIIB, not 7, 8, and 9...

http://knowthatplace.com/

If you just count the columns, then #"IA", "IIA", "IIIB", "IVB", . . . , "VIIIB"# just increases in roman numeral from #1# to #8#, and similarly, #"IA", "IIA", "IIIA", . . . , "VIIIA"# does as well. That's how Mendeleev did it back then, without the #"A"# and #"B"#.

#"A"# is CAS style notation and indicates main group elements, and #"B"# indicates... not main group, i.e. transition metals. More often, it is used in America.

The transition metals start at #"IIIB"# since that is the maximum oxidation state of #"Sc"#. The name of the groups for the #"Fe"#, #"Co"#, and #"Ni"# families don't suggest that, however, and group #"IB"# does not tell us that the maximum oxidation state of #"Cu"# is often cited to be #+2#, not #+1#.

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