Which of the following are acid/base reactions? Select all that apply. NaOH + Fel2=Fe(OH)2 + 2 Nal//
NH3 + HCI --> NHACI
H2O + Cu --> CuO + H2
HNO2 + H2O --> H30* + NO2-
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.