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 you see something that is technically sweet, you go ahead and do it and you argue about what to do about it only after you have had your technical success. That is the way it was with the atomic bomb.”
—J. Robert Oppenheimer (1904–1967)
“The great mass of people ... will more easily fall victim to a big lie than to a small one.”
—Adolf Hitler (1889–1945)
“Other sins only speak; murder shrieks out:
The element of water moistens the earth,
But blood flies upwards, and bedews the heavens.”
—John Webster (1580–1625)