Respuesta :

marymccutchan2
"They have two electrons in the outer shell. Alkali metals are soft, low density metalsthat react vigorously with water to form hydrogen. They only have one electron in it's outer shell. Alkali-earth metals are low density hard metals that react less vigorously with water. They have two electrons in the outer shell."

(Taken from a source)

Hope this helped!

:)
TheBlueFox

Alkali metals and alkaline-earth metals are similar, but they are different in some ways as well. Alkaline-earth metals are slightly less reactive that alkali metals and more dense. Alkali metals have a very low density so they can be cut fairly easily. Both of these metals have a silver color.