Mercury (Hg) is the lightest liquid metal. Its density is 13.6 times more than that of the water. At room temperature, mercury is a liquid. Mercury is the only liquid metal found at normal temperatures.
Caesium (Cs) is a soft, silvery-golden alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature.