David drops a golf ball and a bowling ball at the same time. He then drops a tennis ball and a volleyball. He notices that each pair hit the ground at the same time. Then David picks up a marble and a baseball. If he drops them both at the same time, what can David predict will happen

if he drops them some where there is no air they will both land at the same time as they have no air resistance and gravity pulls every item equally but if they just do it of a building in the middle of the street then the baseball would hit first as it has a larger mass  

Explanation:

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.