The average atomic mass is a number that takes into account the masses of all the different isotopes of a given element AND the proportion in which each is found in the natural state of that element. Hence, it would not make sense to indicate the mass number on the table, as the mass number is different for each different isotope of a chemical element. Isotopes are variants of a particular chemical element: while all isotopesĪ given element share the same number of protons and electrons, each isotope differs from the others in its number of neutrons. All elements exist as two or more isotopes. To understand the subtle but significant difference between mass number and average atomic mass, we need to provide some background: At this point the learners are under the impression that all atoms of a given element are identical. The larger number usually indicated on the table is NOT the mass number (defined as the sum of the number of protons and the number of neutrons), but rather the average atomic mass (this number is usually rounded to the nearest whole number, or to one decimal place).
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |