Why mercury exist in liquid state at room temperature?

Answer 1

The 6s orbital in mercury is particularly stable for a variety of reasons, which results in mercury forming relatively weak metallic bonds and in effect acting as a sort of pseudo- noble gas.

Answer 2

Mercury exists in a liquid state at room temperature because it has a very low melting point of -38.83 degrees Celsius. This is due to the weak metallic bonds between its atoms, allowing them to easily move past each other, resulting in a liquid rather than solid state.