Mass Number - Atomic Mass of An Element

Atomic Mass of An Element

The mass number should also not be confused with the relative atomic mass (also called atomic weight) of an element, which is the ratio of the average atomic mass of the different isotopes of that element (weighted by abundance) to the unified atomic mass unit. This weighted average can be quite different from the near-integer values for individual isotopic masses.

For instance, there are two main isotopes of chlorine: chlorine-35 and chlorine-37. In any given sample of chlorine that has not been subject to mass separation there will be roughly 75% of chlorine atoms which are chlorine-35 and only 25% of chlorine atoms which are chlorine-37. This gives chlorine a relative atomic mass of 35.5 (actually 35.4527 g/mol).

Read more about this topic:  Mass Number

Famous quotes containing the words atomic, mass and/or element:

    When man entered the atomic age, he opened a door into a new world. What we eventually find in that new world, nobody can predict.
    —Ted Sherdeman. Gordon Douglas. Dr. Medford (Edmund Gwenn)

    All great art, and today all great artlessness, must appear extreme to the mass of men, as we know them today. It springs from the anguish of great souls. From the souls of men not formed, but deformed in factories whose inspiration is pelf.
    Alexander Trocchi (1925–1983)

    The reverence for the Scriptures is an element of civilization, for thus has the history of the world been preserved, and is preserved.
    Ralph Waldo Emerson (1803–1882)