Question

Eu (Z = 63) and Yb (Z = 70) show + 2 oxidation state. Explain.

Answer 1

₆₃Eu has electronic configuration, [Xe] 4f⁷5d⁰6s². By losing 2 electrons from 6 s orbital, it acquires stable configuration and 4 f orbital is half filled.

₇₀Yb has electronic configuration, [Xe] 4f¹⁴5d⁰6s² . By losing 2 electrons from 6s orbital, it acquires stable configuration and 4 f orbital is completely filled.
Hence Eu and Yb show 2 + oxidation states.