Answer:
Explanation:
As you move down a group, first ionization energy decreases. WHY? Electrons are further from the nucleus and thus easier to remove the outermost one.
<span>We have ground strate configurations of electrons,if electrons are filled in order of increasing energy. When there are electrons are in higher orbitals, we have an atom in an excited state.
B, and C are excited states.
In B, 2 electrons can fit in the 4s orbital, and that should fill fully before the 4p orbitals.
In C, the same is true for 5s and 5p
In D, this is not an excited state because 4s fills before 3d</span>
The focal length, like you said it's the distance between the FOCAL point and the mirror.
Hope this helps.... :)
