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

Potassium is the most reactive of these metals because it is an alkali metal with one outer electron that it readily loses. Calcium is also reactive, but it loses two outer electrons less readily than potassium. Chromium is a transition metal and is the least reactive of the three in this comparison. So the order from most to least reactive is potassium, calcium, chromium.

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