Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Why Helium is reported with a fractional atomic weight if there is only one isotope of this element?
We know that atomic weight of an element is the result of the average of the atomic weight (or mass) of all the known isotopes for that element. Helium only have one known isotope with atomic mass of 4. Why do the available tables reports a fractional atomic weight (or mass) ?
Maybe I am confused with those concepts.
Thanks for your valuable answers.
1 Answer
- HPVLv 71 decade agoFavorite Answer
According to Wikipedia, He has TWO isotopes: He-3 (0.000137%) and He-4 (99.999863%).
