A diver’s backup oxygen tank reads 900 mm Hg while on her boat, where the temperature is 27 degrees C. When she dives down to the bottom of an unexplored methane lake on a recently discovered moon of Neptune, the temperature will drop to -183 degrees C. What will the pressure in her backup tank be at that temperature?

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.