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GroupsThe vertical columns on the periodic table have special names, too. They are called groups or families. Remember that all elements in a group or family have similar chemical properties (except H in some cases). Each group is represented by a Roman numeral and letter. They are shown in this periodic table at the top of each group. Notice that the first group, the one that starts with H, is represented by Ia and the one right next to it is represented by IIa. Then you have to skip all the way across to boron, B (atomic number 5), to find group IIIa, and then they continue on across--IVa, Va, VIa, and VIIa.
The last group, the inert gases, which is shown here as group 0, is sometimes represented by VIIIa and sometimes by VIII, sometimes by neither one of those, and sometimes it has no label at all. Notice that the groups in the middle part of the table are represented by Roman numerals followed by the letter "b" instead of "a." Those groups with the letter "b" are called the transition metals, or transition elements. Those with the letter "a" (and 0) are called the representative elements. Notice that the transition elements start with group IIIb (not Ib), then IVb, Vb, VIb, VIIb. VIIIb is really weird because sometimes it doesn't have the b and also it represents three vertical columns rather than just one. Then after VIIIb (or VIII) comes Ib and then IIb and we continue on with IIIa and so forth. That is kind of an odd way of making these designations, but it is a useful one. Worse still, there are other ways to number the groups. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Distance Learning questions Clackamas Community College |
