One of the following properties was originally used to arrange elements in the periodic table but is no longer used to organize the modern version which property fits the description

atomic weight or atomic mass.

Explanation:

The development of periodic table starts from the Dobereiner's law of triad where he arranged the elements based on the average of atomic weight of two elements. the middle element was supposed to one with the atomic weight average of the two other elements.

Then the Newland law of octave was proposed where he observed the changes in the periodic trend based on atomic weight after seven elements.

Later Mendleev arranged the elements based on atomic weight only.

Thus the answer is atomic weight or atomic mass.

In modern version we use atomic number to arrange elements.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.