Which statement about elements in the d-block of Period 4 of the periodic table is correct?
Cu\text{Cu}Cu atoms have the electron configuration: 1s22s22p63s23p63d104s11\text{s}^2 2\text{s}^2 2\text{p}^6 3\text{s}^2 3\text{p}^6 3\text{d}^{10} 4\text{s}^11s22s22p63s23p63d104s1.
Fe3+\text{Fe}^{3+}Fe3+ ions contain 4 unpaired electrons.
Zn\text{Zn}Zn forms compounds in a variety of oxidation states.
Sc3+\text{Sc}^{3+}Sc3+ ions have the electron configuration 1s22s22p63s23p63d11\text{s}^2 2\text{s}^2 2\text{p}^6 3\text{s}^2 3\text{p}^6 3\text{d}^11s22s22p63s23p63d1.
