question: What is the third class of elements after metals and nonmetals?
distractor3: noble gases
distractor1: halogens
distractor2: synthetics
correct_answer: metalloids
support: Elements in different groups are lumped together in one of three classes, depending on their properties. The classes are metals, nonmetals, and metalloids. Knowing the class of an element lets you predict many of its properties. The video at the URL below is a good introduction to the classes.