Question

An electron in the 4d6 orbital would have:
more energy than an electron at the 4f6 orbital
more energy than an electron at the 4p6 orbital
more energy than an electron at the 5p6 orbital
more energy than an electron at the 5f6 orbital

Answer 1

n+l rule can help you
higher the n+l for the given orbital higher its energy .
for example
3d and 4s
for 3d n=3 and l=2
n=l =3+2=5
similarly for 4s
n=4 and l=o
n=l=4+0=4
so 3d has higher energy compared to 4s
similarly can u find out for your things