Periodic table gets some flex
Committee’s revisions give chemical isotopes their due
Just as the weight listed on your driver’s license doesn’t necessarily reflect your actual poundage, the official atomic weights of most chemical elements are actually more like ballpark estimates than precise constants. In acknowledgment of this natural variation, the official weights of 10 chemical elements will no longer be expressed as single numbers, but as ranges. The adjustments, published online December 12 in Pure and Applied Chemistry, are the first in an overhaul of the atomic weight of almost every element on the periodic table.
Instead of being described by a single fuzzy number, the atomic weigh
