Element with the electronic configuration as $[Ar{]}^{18}3d^{5}4s^1$ is placed in?

The correct option is D VIB, d-block

Let's look at the electronic configuration of the given element $[Ar{]}^{18}3d^{5}4s^1$.

As we studied in the last chapter we can see that instead of filling 4s fully, the d orbital is half-filled.

Try to recall the concept of fully filled and half-filled orbitals.

Do you remember that fully filled and half-filled orbitals are more stable?

Fully filled and half-filled orbitals are more stable because of symmetric distribution and exchange energy.

Now you can see that the same thing happening in this configuration.Therefore, we can say that this is a d-block element and because its atomic number is 24, it will be placed in VIB group.