The general form of an acid, regardless of strength, is HA, where A is an anion and H is the hydrogen cation or proton ( H ). Properties of anions in solution differ based on the strength of the acid that exists when the anion is protonated. What is the principal difference between a strong acid and a weak acid

i think it's letter a.

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.