Name the members of the lanthanoid series which exhibit +4 oxidation state and those which exhibit +2 oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.
The lanthanides that exhibit +2 and +4 states are shown in the given table. The atomic numbers of the elements are given in the parenthesis.
+2 | +4 |
Nd(60) | Ce(58) |
Sm(62) | Pr(59) |
Eu(63) | Nd(60) |
Tm(69) | Tb(65) |
Yb(70) | Dy(66) |
Ce after forming Ce4+ attains a stable electronic configuration of [Xe].
Tb after forming Tb4+ attains a stable electronic configuration of [Xe] 4f7.
Eu after forming Eu2+ attains a stable electronic configuration of [Xe] 4f7.
Yb after forming Yb2+ attains a stable electronic configuration of [Xe] 4f14.
A certain reaction is 50 complete in 20 minutes at 300 K and the same reaction is 50 complete in 5 minutes at 350 K. Calculate the activation energy if it is a first order reaction. Given: \[ R = 8.314 \, \text{J K}^{-1} \, \text{mol}^{-1}, \quad \log 4 = 0.602 \]
Lanthanoids are at the top of these two-row, while actinoids are at the bottom row.
Lanthanoids are inclusive of 14 elements, with atomic numbers 58-71:
These elements are also called rare earth elements. They are found naturally on the earth, and they're all radioactively stable except promethium, which is radioactive. A trend is one of the interesting properties of the lanthanoid elements, called lanthanide contraction.