An element in this group is attached to the alpha carbon of a carboxylic acid in the Hell-Volhard-Zelinsky reaction. In mass spec, two peaks of equal height (10[1])two units apart characterize a member of this group. (10[1])An atom of a member of this group is displaced (10[1])in a positive silver nitrate (10[1])test. Adding magnesium (-5[1])to hydrocarbons containing a member of this group creates Grignard (“grin-yard”) reagents. These elements, which are denoted with an X in organic structures, can replace hydrogen (10[1])since they both require one more electron for a full outer shell. For 10 points, name this group of elements with seven valence electrons, including fluorine and chlorine. (10[1])■END■ (10[1])