Final answer:
An element with both the highest occupied s sub-level and a filled d sub-level is classified as a metal. This is because such electron configurations are characteristic of metals, particularly those found within the d block of the periodic table which are known for their metallic properties.
Step-by-step explanation:
The question is asking to classify an element whose highest occupied s sub-level and d sub-level are filled. According to the information provided, main group elements include nonmetals, metals, and metalloids and have their valence electrons in the highest n level, which includes s and p orbitals. However, the elements we are interested in are those that have filled d orbitals. These elements do not have partially filled d orbitals but have them completely filled and are often found in the d block of the periodic table.
Transition elements are typically metals, and if they have their d sub-level completely filled, they would fall under this classification, often displaying properties such as conductivity, malleability, and ductility. Hence, the correct classification for an element with both the highest occupied s sub-level and a filled d sub-level would be metal, as nonmetals and metalloids do not fully occupy the d sub-level, and noble gases do not involve d sublevel orbitals at all.
The correct answer to the student's question is: A. Metal.