Which factor plays the most important role in allowing this reaction to occur?
a)temperature
b)concentration
c)pressure
d)surface area

idk what the question is about

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.  

im doing test rn im going with 2 but ill give answer if itss wrong,   : )