If the initial amount of Fe(NO3)3 transferred to the cuvette is 0.039 mol, and the absorbance measurements indicate that 0.011 mol of FeSCN2 are present at equilibrium, what must be [Fe3 ] at equilibrium

right

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.