Areaction is shown below.
what can be concluded about this reaction?
a. a homogeneous catalyst is being used in the reaction.
b. a heterogeneous catalyst is being used in the reaction.
c. a catalyst is not being used in this reaction.
d. an enzyme is being used in this reaction.

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.