Here's why:

* Strong Metallic Bonding: Alkaline earth metals have two valence electrons, which they readily lose to form cations. This strong metallic bonding holds the atoms together tightly in a solid lattice structure.

* High Melting and Boiling Points: Due to the strong metallic bonding, alkaline earth metals have high melting and boiling points, indicating their solid state at room temperature.

Let me know if you have any more questions!