D. the potential energy of the reactants is low; the potential energy decreases gradually; then increases slightly.
Answer: The elements with properties intermediate between those of metals and nonmetals are called semimetals (or metalloids).
Ans is B.Bromine. Only two elements are liquid at room temperature ( mercury and Bromine) . Helium and chlorine, arsenic are gases.
Carbon is 12 grams per mole
