What does a ka value of approximately 1 show about the equilibrium?
A. Very little of the acid has dissociated.
B. The solution can act as both an acid and a base.
C. The acid has completely dissociated.
D. Some of the acid has dissociated.

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.