Fluorine is the most electronegative element, meaning it has a strong tendency to attract electrons. When fluorine reacts with another element, it typically forms a compound where fluorine exists as an anion (F-).
In the compound XF2, the element x must be able to lose two electrons to form a cation (X2+) so that it can combine with two fluoride anions (2F-) to form XF2.
Considering the elements in the periodic table, the element that best fits this description is calcium (Ca). Calcium belongs to Group 2, also known as the alkaline earth metals, which are characterized by their tendency to lose two electrons and form 2+ cations.
When calcium reacts with fluorine, it loses two electrons to form calcium ions (Ca2+), which then combine with two fluoride ions (2F-) to form calcium fluoride (CaF2).
Therefore, the element represented by x is calcium (Ca).
