Question

Which of the following is/are correct regarding Crystal Field Theory (CFT) ?

• A. In an isolated gaseous metal ion, five d orbitals are degenerate
• B. In an isolated gaseous metal ion, no d orbitals are degenerate
• C. If a spherically symmetrical​ field of ligands surrounds ​the metal atom/ion, degeneracy is lost
• D. (a) and (c) above.

Answer 1

The correct option is A In an isolated gaseous metal ion, five d orbitals are degenerate

Assumptions of Crystal Field Theory (CFT) :
In an isolated gaseous metal ion, five d orbitals are degenerate. Orbitals that are identical in energy​ are called degenerate orbitals.
If a spherically symmetrical​ field of ligands surrounds ​the metal atom/ion,this degeneracy ​is still maintained.​
​When there is a negative field due to ligands in a complex (Either anions or the negative​ ends of dipolar molecules​ like $N{H}_3$ and $H_{2}O$) , it becomes asymmetrical and the degeneracy of the d-orbitals is lost. This results in splitting of d-orbitals.