Lanthanides are associated with the filling of 4f-orbitals while actinides are engaged with the filling of 5f-orbitals. The coupling energy of 4f-electrons is nearly not as much as that of 5f-electrons. The protecting impact of 5f-electrons is less powerful when contrasted with that of 4f-electrons.
Lanthanides are involved in the filling of 4f-orbitals whereas actinides are involved in the filling of 5f-orbitals. The binding energy of 4f-electrons is comparatively less than that of 5f-electrons. The shielding effect of 5f-electrons is less effective as compared to that of 4f-electrons.
The magnetic properties of the lanthanides are due to the electrons in the partial filled 4f shell. The magnetic properties of the first-row actinides are due to the electrons in the partial filled 5f shell.