So, remember the periodic table? That thing in chemistry class your teacher probably introduced to you with a song by Tom Lehrer? Yeah, it wasn’t correct.
Not the order of the elements or anything, or the atomic numbers, just the atomic weights. A quick refresher: the atomic weight is how much a mole of one element weighs. No, not when you make a delicious Mexican sauce out of it, although you haven’t lived until you’ve tasted a selenium mole sauce. No, we mean in a scientific sense, how much a sample of 6.023 times 10 to the 23rd power weighs (As to why that’s not in scientific notation, it’s because there’s a word problem later in the post).
Basically, instead of just theorizing based on the weight of one atom, we’ve actually gone out and put together pure moles of lots of elements at this point, and we have a much better idea of which isotopes are more likely to be present. For example, a mole of carbon is going to be heavy on the carbon-12, because there’s a lot of that stuff in nature. So the University of Calgary issued some revisions.
At least that’s what you’ll believe if you take the blue pill.
[ via the agents at Ars Technica ]