Calcium, magnesium, and strontium are near each other on the periodic table and have some characteristics in common, but they differ in chemical reactivity. Which lists these metals in order from most reactive to least reactive?

Calcium, magnesium, and strontium are all Group 2 metals. Reactivity generally increases down the group, so among these three, strontium is most reactive, calcium is next, and magnesium is least reactive. Therefore, the correct order is strontium, calcium, magnesium.

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