Why do mercury hardly evaporates in room temperature

All I can say is that Mercury is a liquid at room temperature, and liquids will very slowly evaporate at room temperature. This is because the molecules have a relatively low energy at room temperature (since room temperature is very low compared to boiling point). The boiling point of mercury is 356.73 degrees Celsius, and room temperature is only about 23 degrees Celsius, so the evaporation rate at room temperature would be little to nothing.