This page explains methods for determining chemical mass and traces the historical development of atomic weight from John Dalton's initial concepts based on hydrogen to modern understandings involving...This page explains methods for determining chemical mass and traces the historical development of atomic weight from John Dalton's initial concepts based on hydrogen to modern understandings involving protons and neutrons. It defines mass number as the sum of protons and neutrons, providing examples from the first six elements of the periodic table, including a detailed look at helium, and illustrates how to calculate the number of neutrons based on mass and atomic numbers.
