Which statement about the chemistry of d-block elements is correct?
Sc3+\text{Sc}^{3+}Sc3+ and Zn2+\text{Zn}^{2+}Zn2+ ions form colorless aqueous solutions because neither ion has a partially filled d sub-shell.
A chromium atom in its ground state has the electronic configuration [Ar]3d44s2[\text{Ar}]3\text{d}^4 4\text{s}^2[Ar]3d44s2.
In the formation of a Fe2+\text{Fe}^{2+}Fe2+ ion from an iron atom, electrons are lost from the 3d3\text{d}3d sub-shell before the 4s4\text{s}4s sub-shell.
The color of transition metal complexes arises because d-electrons emit visible light when they fall from a higher energy d-orbital to a lower energy d-orbital.
