What is the electronic structure of v2+?

V²⁺ =  [Ar] 3d³

Explanation:Elements can either lose or gain an electron(s) to attain an octet configuration and form ions.Metals lose an electron(s) to attain a stable configuration and form positively charged ions called cations.Non-metals, on the other hand, gain an electron(s) to attain an octet configuration and form negatively charged ions known as anions.In this case, Vanadium is a transitional element with 5 valence electrons.Like other transition elements, vanadium may have multiple oxidation numbers. Vanadium has an atomic number of 23 and a configuration of [Ar] 3d³4s², therefore, vanadium ion (V²⁺) formed by loss of two electrons will have a configuration of [Ar] 3d³

Burned piece of steel wool does not gain mass. so only d could be true.