Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

A 2001 J.C. Alvarez study investigated properties of aromatic polyamides containing this class of elements, and they are reacted with carboxylic acids in the Hunsdiecker reaction. The Finkelstein reaction involves the exchange of two atoms of these elements, and the enrichment of uranium via gaseous diffusion is accomplished using a molecule containing the simplest of these elements, whose synthesis won Henri Moissan the 1906 Nobel in Chemistry. Another member of this group is used as a mordant in Gram staining and has an important role in the thyroid gland. For 10 points, identify these highly reactive Group 17 elements that include iodine and fluorine.
Science