What is the correct equilibrium expression for the dissociation of the base pyridine: C5H5N + H2O ⇋ C5H5NH+ + OH-

A. Kb = [C5H5NH+][OH-] / [C5H5N]
B. Kb = [C5H5N][OH-] / [C5H5NH+][H2O]
C .Kb = [C5H5NH+][OH-] / [C5H5N][H2O]
D .Kb = [C5H5NH+][C5H5N] / [OH-]
E. Kb = [C5H5N][OH-] / [C5H5NH+]

the answer is d.) potassium

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.