Periodic table is revised

Science News : Just as the weight listed on your driver’s license doesn’t necessarily reflect your actual poundage, the official atomic weights of the chemical elements are actually more like ballpark estimates than precise constants, according to Rachel Ehrenberg writing for Science News. In acknowledgment of that natural variation, the official weights of 10 chemical elements will no longer be expressed as single numbers, but as ranges. The adjustments, published online on 12 December in Pure and Applied Chemistry, are the first in an overhaul of the atomic weight of almost every element on the periodic table.