Whichis not true?
A. In the hydrogen atom, all subshells of a principle shell are at the same energy level.
B. Orbital energies are higher in multielectron atoms than in hydrogen atomes.
C. In a multielectron atom, the various subshells of a principle shell are at a different energy levels.
D. All orbitals within a subshell of a multielectron atom are at the same energy level.
E. In high numbered principal shells of a multielectron atom, some subshells of differetn princpal shells have nearly identical energies.
If we ignore the very small perturbations due to spin-spin and spin-orbit interactions (such as in the super-fine structure of hydrogen), then we can say that the energy level of hydrogen's electron is determined by the principal quantum number n - so A is true.
B is also true. ...
It investigates the energy of orbitals.