What is the relative atomic mass?

The relative atomic mass is determined as the weighted mean of the masses of all naturally occurring isotopes of an element, taking into account their relative abundance. This means that the relative atomic mass reflects not only the masses of the different isotopes but also how much of each isotope is present in a sample of the element.

For example, if an element has two isotopes with different masses and abundances, the relative atomic mass will be a calculated average that favors the isotope that is more abundant. This value is often found on the periodic table and is essential for various calculations in chemistry, such as determining the amounts of substances in chemical reactions.

While the total mass of a compound and the mass of one mole of an element are related concepts, they do not describe the relative atomic mass, which is specifically focused on isotopic composition. The average mass of all isotopes could be misleading, as it must include their abundances to be accurate, differentiating it from the weighted mean definition that is more precise.