Answer:
d. Transition metal
Explanation:
A transition metal is an element which has an atom or forms an ion with a partially-filled d-subshell.
As we can see from the electronic configuration of Copper 2+ ion, Cu²⁺:
[tex]_{27}Cu^{2+} = 1s^2\space\ 2s^2 \space\ 2p^6 \space\ 3s^2 \space\ 3p^6 \space\ 3d^9[/tex] ,
copper forms an ion with an incomplete d-subshell that contains 9 electrons; therefore copper is a transition metal.
• Option a. is wrong because copper is not a metalloid. Metalloids have characteristics of both metals and non-metals; copper only has metallic properties.
• Option b. is wrong because 'alkaline earth metals' are the elements in Group 2 of the periodic table; copper is in Group 11.
• Option c. is wrong because 'alkali metals' are in Group 1 of the periodic table.
