Atomic+Mass+Units+and+the+Angstrom

=Atomic Mass Units and the Angstrom= ** __Atomic Mass Units (amu)__** Atomic Mass Units (amu) is a unit of mass used to express atomic and molecular masses. A more precise definition is that atomic mass unit is one-twelfth of the mass of an isolated carbon-12 (¹²c ) at rest and in its ground state. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass about 1 amu.
 * It is based on the value of exactly 12 amu for the mass of the isotope of carbon that has six protons and six neutrons in the nucleus.
 * The unit is expressed as "amu".
 * A single amu weighs about 1.660 538 782 x 10-²⁴ g.
 * The accepted standard is now the unified atomic mass unit (symbol u), with: 1 u = 1.000 317 9 amu (physical scale) = 1.000 043 amu (chemical scale).

__**Angstrom**__
The angstrom (symbol Å) is an internationally recognized unit of length equal to 1 x 10-¹⁰ meters.
 * Equal to 0.1 nanometers.
 * Named after Anders Jonas Ångstrom, a Swedish physicist and a founder of the science of spectroscopy.
 * Not formally defined within the International Systems of Units (SI) but is accepted for use.
 * Often used to express the size of atoms.

http://www.sizes.com/units/atomic_mass_unit.htm