The teams go from 1 to 18 in the regular table. Once looking at the change metals in the routine table, You watch roman numerals labelled v "B," in the order of III, IV, V, VI, VII, VIII, VIII, VIII, I, II. Why walk III - VIII come before I and also II? and also why walk VIII acquire repeated 3 times?

Also, what is the distinction in the groups labelled A and B, as well as the fact that the B teams are the change metals?


*

Even though your question obtain downvoted, ns think the is one legitimate question for human being to understand the trend. I think I-VIII Roman character nomenclature belong come CAS mechanism while 1-18 Arabic numeral groups are encourage by IUPAC (Ref.1). The IUPAC recommended routine Table is given listed below (ignore the roman numerals, i beg your pardon I put in over there to explain):

*

According to Ref.1, the man of routine Table of elements has been addressed together follows:

H.G. Deming provided the lengthy periodic table in his textbook basic mslsec.com (See adhering to diagram v Roman number only; Ref.2), which appeared in the USA because that the very first time in 1923, and also designated the an initial two and also the last five Main groups with the notation "A", and the intervening transition Groups v the notation "B". The numeration was preferred so the the characteristics oxides the the B teams would exchange mail to those of the A groups. The iron, cobalt, and also nickel groups were designated neither A nor B. The Noble Gas group was initially attached by Ueming come the left side of the regular table. The team was later switched come the best side and usually labeling as group VlllA. This version of the regular table was dispersed for countless years by the Sargent-Welch scientific Company, Skokie, Illinois, USA. $<\cdot\cdot\cdot>$

The designations A and B have been extensively and rather arbitrarily used in the meantime in textbooks and in publications. An investigation of the applications of the subgroup designations A and B in all articles, which appeared between 1972 and also 1981 and covered by chemical Abstracts, revealed a completely arbitrary usage of the designation. Moreover, much more than 10% that the short articles it was practically impossible, indigenous the wording that the text, to acknowledge which facets were being discussed without more information (Ref.3).

You are watching: Periodic table with roman numeral groups

*

The IUPAC board of directors on the Nomenclature of inorganic mslsec.com (CNIC) propose the designations of groups by Arabic number in 1984 (Ref.4), which was approved by the Nomenclature board of directors of the American Chemical culture (ACS) and rest is history.

Thus, it is for sure to say that this nomenclature is currently outdated and also not precious discussing.

References:

Horace Grove Deming, General mslsec.com; J.

See more: Solved: 15 Is 40 Percent Of What Number Is 15 Of 40 ? 15 Is 40 Percent Of What Number

Wiley & Sons, Inc.: new York, NY, 1923.