Given the reaction: HNO2 (aq) <-> H+ (aq) + NO2- (aq); write the ionization constant for the reaction.

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom. 

Hello thereone of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description? answer: atomic mass  was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.