Duct till simply means they're stretchy or stretchable malleable simply means we can hammer them into thin sheets of metal and soft. Well, it simply means they're soft. These guys also display lust alike properties, which simply means they are shiny. Now, metals are shiny, so that makes sense. And these guys, because they're metals, they conduct electricity. In other words, electrons are capable of moving from one point to another in alkali metals very easily.