Carbon-12 is assigned a mass of exactly 12 unified atomic mass units. So how come it doesn't say exactly 12 on the periodic table? Because there's more than one kind of carbon. In this video, we work through two examples of determining the average atomic mass for an element - which is a weighted average of all the different isotopes of that element. We'll be your very own homework tutor for chemistry!
Carbon-12 is assigned a mass of exactly 12 unified atomic mass units. So why doesn't it say exactly 12 on the periodic table? Because there's more than one kind of carbon.
In this video, we work through two examples of determining the average atomic mass for an element - which is a weighted average of all the different isotopes of that element.
A prerequisite for this video is an understanding of isotopes. If you need a quick refresher on the topic of isotopes, watch our very short (under 1 minute) definition from our chemistry glossary.
Video: Average Atomic Mass (amu, Daltons)
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