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Text and/or other creative content from Relative atomic mass was copied or moved into Standard atomic weight with this edit. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists. |
It isn't a lot of help when the usual term for a thing is wrong by reason of slang. What is seen in interval notation on periodic tables is the STANDARD atomic weight. That is the value of atomic weight you expect from many samples on Earth, and hence the interval! The atomic weight of a SINGLE sample in a lab can be determined far more accurately with a mass spectrograph, even though usually more than one isotope is being evaluated, and their weighted sum used. That atomic weight can differentiate between samples, using stable isotope ratios. For example, it is differences in atomic weights of carbon from natural testosterone vs. artificial testosterone (which has a carbon atomic weight that looks like a plant) that allows doping commissions to tell if testosterone is taken artificially. Yet all these values are within the "standard atomic weight" for carbon seen on the average periodic table. That is why the two terms are different.
The term "relative atomic mass" is the same as "atomic weight". It is NOT the same as "standard atomic weight." That latter term would need to be "standard relative atomic mass" which is so long it is rarely seen. This is one reason that "atomic weight" continues to hang on. S B H arris 03:30, 7 September 2017 (UTC)
Changes to the standard atomic weights of 14 chemical elements have been recommended recently ( [1]), this should be incorporated into the article and values be updated accordingly. Szaszicska ( talk) 21:26, 7 October 2018 (UTC)
References
About atomic weight's data we are using.
The physical quantity standard atomic weight (Ar) is dimensionless by definition. So: the value has no unit after the number.
Different is: physical quantity Atomic mass (ma or m), it has unit: Da or u.
Lambiam tried to clarify this in this GF edit, but the wording was incorrect so I had to revert. It is not that "the unit is 'u' and is just not mentioned". The unit mathematically and formally disappears because the measured mass (an m so has unit u!) is devided by the purpously defined mass, the 12C mass (also unit u!). The devision cancelles both units, that is how it becomes dimensionless.
Sure this should be described much much better in the article and in the lede, as Lambiam initiated. Even before the "mix of isotopes" part. I myself could not create it, but others including Lambiam might give it a go. Have a nice edit. - DePiep ( talk) 19:57, 26 October 2020 (UTC)
This
level-5 vital article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||||||
|
Text and/or other creative content from Relative atomic mass was copied or moved into Standard atomic weight with this edit. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists. |
It isn't a lot of help when the usual term for a thing is wrong by reason of slang. What is seen in interval notation on periodic tables is the STANDARD atomic weight. That is the value of atomic weight you expect from many samples on Earth, and hence the interval! The atomic weight of a SINGLE sample in a lab can be determined far more accurately with a mass spectrograph, even though usually more than one isotope is being evaluated, and their weighted sum used. That atomic weight can differentiate between samples, using stable isotope ratios. For example, it is differences in atomic weights of carbon from natural testosterone vs. artificial testosterone (which has a carbon atomic weight that looks like a plant) that allows doping commissions to tell if testosterone is taken artificially. Yet all these values are within the "standard atomic weight" for carbon seen on the average periodic table. That is why the two terms are different.
The term "relative atomic mass" is the same as "atomic weight". It is NOT the same as "standard atomic weight." That latter term would need to be "standard relative atomic mass" which is so long it is rarely seen. This is one reason that "atomic weight" continues to hang on. S B H arris 03:30, 7 September 2017 (UTC)
Changes to the standard atomic weights of 14 chemical elements have been recommended recently ( [1]), this should be incorporated into the article and values be updated accordingly. Szaszicska ( talk) 21:26, 7 October 2018 (UTC)
References
About atomic weight's data we are using.
The physical quantity standard atomic weight (Ar) is dimensionless by definition. So: the value has no unit after the number.
Different is: physical quantity Atomic mass (ma or m), it has unit: Da or u.
Lambiam tried to clarify this in this GF edit, but the wording was incorrect so I had to revert. It is not that "the unit is 'u' and is just not mentioned". The unit mathematically and formally disappears because the measured mass (an m so has unit u!) is devided by the purpously defined mass, the 12C mass (also unit u!). The devision cancelles both units, that is how it becomes dimensionless.
Sure this should be described much much better in the article and in the lede, as Lambiam initiated. Even before the "mix of isotopes" part. I myself could not create it, but others including Lambiam might give it a go. Have a nice edit. - DePiep ( talk) 19:57, 26 October 2020 (UTC)