Out of all the elements of the Periodic Table, how many are liquid at scientific room temperature?

There are two elements that are liquid at the temperature technically designated 'room temperature', and a total of six elements that can be liquids at actual room temperatures and pressures.

Room temperature, in science, is defined to mean anywhere from 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit). At this temperature, and ordinary pressure, only two elements are liquids:

Bromine and Mercury.

Bromine (symbol Br and atomic number 35) is a reddish-brown liquid, with a melting point of -7.25 degrees Celsius (18.95 degrees Fahrenheit).

Mercury (symbol Hg and atomic number 80) is a toxic shiny silvery metal, with a melting point of -38.83 degrees Celsius (-37.984 degrees Fahrenheit).

When the temperature is slightly warmer, there are a few other elements found as liquids at normal pressure:

Francium

Cesium

Gallium

Rubidium

These four elements all melt at temperatures slightly higher than scientific room temperature.