Synthetic
This is the atomic weight of the element.
... atomic mass or atomic weight.
Atomic weight, if the average is taken by weighting the mass of each naturally occurring isotope by its natural abundance.
Atomic weight or gram-atomic mass.
Lead is an element---Go to http://en.wikipedia.org/ and look up lead---Natural or Synthetic is irrelevant when you're talking about elements. (If you don't know what I'm talking about, then maybe you ought to also read the wikipedia article on Chemical Element.)
3 quarters of the 90 naturally occurring elements are called metals.
An elemental mineral.
The weighted average of all of the natural occuring isotopes for a particular element is called its Atomic Weight (or Relative Atomic Mass)
The weighted average of all of the natural occuring isotopes for a particular element is called its Atomic Weight (or Relative Atomic Mass)
The atomic weight of the element.
Isotopes - atoms with the same atomic number, number of protons and number of electrons
This is the atomic weight.