2026 End Of Year Science Vocabulary Competition Practice Test

Group 17 consists of highly reactive nonmetals known as halogens. These elements all have seven valence electrons, so they eagerly gain one more to complete an octet. That drive to achieve a full outer shell makes them extremely reactive, especially with metals to form salts. In their elemental form, they appear as diatomic molecules such as F2 and Cl2, and they are highly electronegative, which fuels their tendency to attract electrons from others. The name halogen means "salt-former," highlighting their common ability to form salts with metals. Noble gases are inert and sit in a different group with full octets and very low reactivity. Metalloids act as intermediates between metals and nonmetals, not forming the same highly reactive nonmetal behavior. Transition metals are a separate block of metals with different properties and oxidation states.