Now, let's look at the second type of group right next to our alkaline metals, known as alkaline earth metals. Now, these guys are obviously in group two or group two A on our periodic table. And these guys, just like the alkaline metals, are also part of the metal division. So they're metals. But unlike these guys, which are soft, these guys are harder and more dense. That means their molecules in a solid state are closer together per unit volume.