Only two elements on the periodic table are elements at room temperature. They are mercury (a metal) and bromine (a halogen).
Four other elements are liquids slightly warmer than room temperature. They are francium, cesium, gallium, and rubidium (all metals).
The reason these elements are liquids has to do with how tightly bound their electrons are to the atomic nucleus. Basically, the atoms don't share their electrons with nearby atoms, so it is easy to separate them from solids into liquids.