What about the similar configurations of those elements causing them to all be shiny?
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The ability to reflect light is a characteristic of all metals, not just the alkaline earths. They have just a few electrons in their valence shells, causing almost all wavelengths of light to be reflected back.
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All metals are shiny. It has something to do with electrons and their conductivity; I can't really give you an answer. But another fact is that light reflected off a nonconducting surface like glass is polarized while light reflected off a metal surface isn't polarized. You can check this out with a pair of polarized sunglasses.