Answer:
Arsenic
Step-by-step explanation:
From the introduction given in the question, the element we are considering must be a member of group 15 because of its similarity to nitrogen.
We were also told that it exhibits the characteristics of metals and some nonmetals hence the element is a metalloid.
Lastly we were told that it contains 3d but not 4d electrons. This has ruled out antimony. Our only element standing now is arsenic!
The electronic configuration of arsenic is; [Ar] 3d¹⁰ 4s² 4p³. Hence the correct answer is arsenic.