NUMBER@1 NUMBER@2 | - style = `` background-color : #c 0ffff '' | Argon | | Ar | | NUMBER@3 | | NUMBER@4 -LRB- NUMBER@5 -RRB- The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given .

NUMBER@1 NUMBER@2 | - | Argon | | Ar | | NUMBER@3 | | NUMBER@4 -LRB- NUMBER@5 -RRB- The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given .
