Atomic mass and formula
Average atomic mass The weighted average of the masses of the
isotopes of an element.
Molecular Formula is a chemical formula of a molecular compound
that shows the kinds and number of atoms present in a molecule of a
compound. (H2O)
Molar mass A term used to refer to the mass of a mole of any
substance. C =12 grams
Atomic Mass Unit A unit of mass equal to 1/12 the mass of an atom
Of the most common isotope of carton (carbon 12),which is assigned a
mass of 12. Examples C= 12 grams. AMU is = to 1/12 of a carbon atom or
Hydrogen=l gram
Isotope- One of two or more species of atoms of a chemical element having nuclei
with the same number of protons but different numbers of neutrons. They have the
same atomic number of protons but different numbers of neutrons. They have the
same atomic number and hence nearly identical chemical behavior but different
atomic masses.
Most elements found in nature are mixtures of several isotopes
Carbon-14, for instance, is used for estimating the age of objects within a relatively
recent span of time-up to about 5,000 years-where as
geologists and other scientists use uranium-238 to date minerals of an age
on a scale with that of the Earth.