Question

Discuss the main points of similarity between lanthanoids and actinoids.

Give three properties in which actinoids resemble lanthanoids.

Write two similarities between lanthanoids and actinoids.

Answer 1

Lanthanoids and actinoids share similar features due to their (n − 2) f-subshell filling and outer electronic structure. The primary commonalities are as follows.

1. Lanthanoids and actinoids have the same main oxidation state of +3.
2. Both involve the filling of (n − 2) f-orbitals.
3. Both are very electropositive and extremely reactive.
4. Both display a decrease in atomic and ionic size (lanthanoid contraction and actinoid contraction) when the atomic number increases.
5. Both show magnetic properties.
6. Lanthanoids and actinoids form soluble nitrates, sulphates, and perchlorates during +3 oxidation, but insoluble hydroxides, carbonates, and fluorides.