you can see what i mean here: http://en.wikipedia.org/wiki/Isotopes_of_aluminium
what does that mean?
2006-10-14 13:41:01 · 2 answers · asked by um yea hi 4 in Science & Mathematics ➔ Chemistry
It means that that nucleus is in a metstable excited state. Such nuclei are called "metstable nuclear isomers". (The "m" you are asking about stands for "metastable".)
Typically, after a nuclear decay process, the daughter nucleus is left in an excited state, which then decays to the ground nuclear state, usually by the emission of a gamma photon. Some excited states are relatively long-lived, because the transition to the ground state is "forbidden" by quantum mechanical selection rules. These are metastable isomers and get tagged with an "m" after the mass number.
Some metastable isomers are very nearly stable. Ta-181m has a halflife of 10^15 years!
2006-10-14 14:02:21 · answer #1 · answered by hfshaw 7 · 2⤊ 0⤋
gee molar # did that give you the information you missed while sleeping in class
2006-10-14 20:45:18 · answer #2 · answered by Anonymous · 0⤊ 2⤋