Question

1. choose the best answer. used in electronic devices, __ conduct electricity under special conditions. noble gases alkali metals transition metals semiconductors 20. choose the best answer. the __ have the properties of both metals and nonmetals and are found in the \in - between\ a radioisotopes metalloids noble gases lanthanide series

Explanation:

1. Semiconductors are materials that can conduct electricity under special conditions like changes in temperature, light - exposure, or addition of impurities. They are widely used in electronic devices such as transistors and integrated circuits. Noble gases are inert and do not conduct electricity easily in normal or special conditions for electronic device applications. Alkali metals are highly reactive and not used for their conductivity in special conditions in electronics. Transition metals are good conductors in general conditions, not under special conditions as described for semiconductors.
2. Metalloids have properties intermediate between metals and non - metals. They are found in the "in - between" area of the periodic table. Radioisotopes are isotopes with unstable nuclei and have nothing to do with the properties of metals and non - metals in this context. Noble gases are non - metals with distinct properties and not in the "in - between" category. The lanthanide series is a group of metals and does not have the combined metal and non - metal properties described.

Answer:

1. D. semiconductors
2. B. metalloids