During a reaction involving the formation of a complex ion, which of the following are true when Q=Kf? a. No net increase in the concentration of the complex ion is observed.
b. The reaction is at equilibrium.
c. The solution is saturated in the complex ion
d. None of the above

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.