973 770 171 32 3 | Objectors to the name usually prefer the term "relative atomic mass" not to be confused with |
---|---|
Silicon exists in nature as a mixture of three isotopes: 28 Si, 29 Si and 30 Si | 0854 The estimation of the is complicated, especially as the is not necessarily symmetrical: the standard atomic weights are quoted with estimated symmetrical uncertainties, and the value for silicon is 28 |
The term "relative atomic mass" of the element may also be used to describe this physical quantity, and is synonymous with it.
9For example, from has a lower atomic weight than boron from , because of its different | , which is not a quantity• 976 926 532 46 194 92 |
---|---|
The atomic masses of these nuclides are known to a precision of one part in 14 billion for 28 Si and about one part in one billion for the others |
it is not uncommon to have misleading names of physical quantities which are retained for historical reasons, such as• Indeed the continued use of the term "atomic weight" has attracted considerable controversy since at least the 1960s see below.
Nevertheless, given the cost and difficulty of , it is usual to use the tabulated values of standard atomic weights which are ubiquitous in chemical laboratories | These standard atomic weights are reprinted in a wide variety of textbooks, commercial catalogues, wallcharts etc |
---|---|
Atomic weights, unlike the masses of individual atoms, not to be confused with relative atomic mass , are not , but vary from sample to sample of elements that are not | In reply, supporters of the term "atomic weight" point out among other arguments that• The latest edition is 2006 |
, and in the table below.
25