Which of the following element groups is NOT included in the representative elements?

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11ecba2d_11db_e1aa_a3bf_27bf9b94fd56_MD0008_00 The representative elements (also called the main group elements) are the elements in Groups 1-2 and Groups 13-18 on the periodic table. These elements are so called because they are the most abundant elements in nature and provide a wide representation of the elemental and chemical characteristics found in natural systems. With respect to atomic electronic configurations, the representative elements are those elements found in the s-block and the p-block of the periodic table. The s-block elements have valence electrons of highest energy occupying an s orbital whereas the p-block elements have valence electrons of highest energy occupying a p orbital. An alternative numbering system for the element groups involves a number (sometimes expressed as a Roman numeral) along with a letter (A or B). Although this older numbering system is now considered obsolete, it is sometimes still used because, for the representative elements, it correlates to the number of valence electrons in each group (with the exception of helium). For example, elements in Group 3A each have three valence electrons. (Choice A) Group 1 (1A) is part of the s-block elements and is included in the representative elements. (Choices C and D) Group 13 (3A) and Group 18 (8A) are part of the p-block elements and are included in the representative elements. Educational objective: The representative elements (main group elements) are the elements in Groups 1-2 (1A-2A) and Groups 13-18 (3A-8A) that are contained in the s-block and the p-block, respectively, of the periodic table.

Which of the Following Element Groups Is NOT Included in the Representative