Here's why:

* Strontium's Position on the Periodic Table: Strontium is in group 2 of the periodic table, also known as the alkaline earth metals.

* Electron Configuration: Strontium has two electrons in its outermost shell (valence electrons).

* Tendency to Lose Electrons: Elements in this group have a strong tendency to lose these two valence electrons to achieve a stable electron configuration like the noble gases.

Therefore, strontium readily forms a +2 cation (Sr²⁺) by losing two electrons.