The correct order of relative stability of half-filled and completely filled subshells is?
As we know from our knowledge of atomic structure, if we are talking about the same principle quantum number, then p-orbitals are more stable than d orbitals.
But a completely filled d-orbital is more stable than a half-filled p-orbital because then it does not need more electrons to complete its orbital.
Hence, the correct order of relative stability of half-filled and completely filled sub-shell is d5 < p3 < d10 < p6.