Answer:
Option B
Explanation:
First, we need to know what is an energy level.
An energy level corresponds to the row of the periodic table of element. So, if you see the attached picture, you can see that we have 7 rows where the elements are distributed, so, we have 7 energy levels for all those elements.
Knowing that, the sub levels are the caps where the electrons of the atoms are carried. These sublevels or caps, are called orbitals, these can be of several types
s orbytal: can hold 2 electrons
p orbytal: can hold up to 6 electrons.
d orbytal: can hold up to 10 electrons
f orbytal: can hold up to 14 electrons
g orbytal: can hold up to 18 electrons.
Depending on the row (or energy level) and the atom, we can know how many electrons can carry an element, in which period or row is, and the sub levels. For example, the Chlorine, with an atomic number of 17, can carry up to 7 electrons in it's outer level and it's on the third row (two energy levels). This can be known with it's electronic configuration:
[Cl] = 1s^2 2s^2 2p^6 3s^2 3p^5
The last energy level is 3, so it's the third period, and the electrons of those sub level are 2 and 5, 7 electrons.
Hope this can help better
