8. What is the lanthanide’s final element? a) Ytterbium b) Erbium c) Thulium d) Lutetium
Answer: d Explanation: Erbium, Thulium, Ytterbium, and Lutetium have atomic numbers of 68, 69, 70, and 71, respectively. Lutetium, the final element in the lanthanide family, has the electrical configuration [Xe]4f145d16s2.