Answer: both options A and D
Explanation:
Half filled and completely filled orbitals are more stable than any other configuration since they are more symmetrical and energy exchange Occurs readily.
So 4f^7& 4f^14 are more stable
C. Distance from Earth
The observed brightness of a star (the apparent magnitude) to an absolute magnitude, you need to know the distance [d], to the star. Alternatively, if we know the distance and the apparent magnitude [m] of a star, we can calculate its absolute magnitude [d].
*paraphrased from "COSMOS.com"
I’m pretty sure it’s abode and cathode
