The atomic mass of an element is the average mass of the different isotopes of the element. The atoms in the periodic table are arranged to show characteristics and relationships between atoms and ...

Why do the atomic weights on the periodic table keep changing? Kit Chapman meets the team behind the decimal places ...

Last year, the International Union of Pure and Applied Chemistry (Iupac) revised the atomic weights of gadolinium, lutetium and zirconium. Gadolinium’s standard atomic weight changed from 157.250 to ...

In those cases the atomic mass listed on the periodic table has traditionally been defined as an average depending on how common each isotope is in nature. But that average is not the same every ...

For example, sulfur is commonly known to have a standard atomic weight of 32.065, but its real atomic weight can be anywhere between 32.059 and 32.076, depending on where the element is found.

Magnesium’s atomic weight, meanwhile, was formerly 24.3050, but is now represented by the interval [24.304, 24.307]. More to come ...