Which of these materials are usually poor conductors of heat and electricity?1 pointAlkaline earth metalsAlkali metalsNonmetalsMetalsMetalloids

To determine which materials are usually poor conductors of heat and electricity, we can analyze the properties of each group mentioned:

1. Alkaline Earth Metals: These are good conductors of heat and electricity, as they are metals.

2. Alkali Metals: Similar to alkaline earth metals, alkali metals (like sodium and potassium) are also good conductors due to their metallic properties.

3. Nonmetals: Nonmetals are typically poor conductors of heat and electricity. This group includes elements such as sulfur, phosphorus, and chlorine, which lack the free electrons that facilitate conduction.

4. Metals: Metals are well-known for their high conductivity of heat and electricity due to the presence of free-moving electrons.

5. Metalloids: Metalloids have intermediate properties and can conduct electricity better than nonmetals, but they are still not as good as metals.

Conclusion

Among the options listed, nonmetals are typically poor conductors of heat and electricity.