an ultraHIGH vacuumk system operates at a pressure of what is the concentration of residual air molecxules

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.

27. =3,500,000 x 4,000 = 14,000,000,000

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