Question

In most of the lanthanides, the penultimate shell contains ..... electrons in s,p orbitals.

• A. 6
• B. 7
• C. 8
• D. 10

Answer 1

The correct option is C 8

It is considered that the 5d orbital remains vacant and the electrons enter into the 4f orbital. Hence, as electrons enter $n-1$ shell it is called as anti penultimate shell.

Hence, before filling d orbital surely it might have filled s and p orbitals in which we can accommodate 8 electrons.

Hence, in most of the lanthanides, the penultimate shell contains 8 electrons in s and p orbitals.

Option C is correct.