How will you prepare 500 ml of 0.750 M citrate buffer with pH of 4.25 from solid citric acid (H3C6H5O7) and solid sodium citrate (NaH2C6H5O7). The Ka of citric acid is 7.40 x 10-4.

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.