Strontium (Sr) is located in period 5 of the periodic table. This means it is situated in the fifth row, which includes the elements that have their outermost electrons in the fifth energy level.
To elaborate, the periodic table is organized into periods and groups. Each period represents the number of electron shells that the elements in that row possess. Strontium, being an alkaline earth metal, has two electrons in its outermost shell, which contributes to its chemical properties and reactivity. Thus, understanding its position in period 5 helps in predicting its behavior in chemical reactions and its interaction with other elements.