Which is the least reactive sulfur, chlorine, bromine, or selenium?

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

Explanation for basic character?

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.