Answer: The element is Magnesium.
Explanation:
The energy levels determine the period of the element. Thus an element with 3 energy levels will be an element of third period.
As the valence electrons are 2 , the group number of the element is 2.
Thus the element will have an electroni configuration of [tex]1s^22s^22p^63s^2[/tex]
The atomic number will be equal to the number of electrons and thus atomic number will be (2+2+6+2) = 12. The element will be magnesium with atomic symbol of Mg.
