To calculate the relative atomic mass (also known as atomic weight or atomic mass), you need to consider the masses and abundances of the isotopes of the element. Here's a step-by-step process to calculate the relative atomic mass:
Determine the isotopes: Identify the isotopes of the element and their respective abundances. Isotopes are variants of an element that have the same number of protons but different numbers of neutrons in their nuclei.
Find the atomic mass of each isotope: Look up the atomic mass of each isotope from reliable sources such as the periodic table or other reference materials. The atomic mass is typically given in atomic mass units (AMU) or unified atomic mass units (u).
Multiply the atomic mass by the abundance: Multiply the atomic mass of each isotope by its abundance expressed as a decimal. The abundance represents the fraction or percentage of that isotope in a naturally occurring sample of the element.
Sum up the results: Add up the products obtained from step 3 to calculate the weighted average. This sum represents the relative atomic mass of the element.
Here's a formula to represent the calculation:
Relative Atomic Mass = (Mass of Isotope₁ × Abundance of Isotope₁) + (Mass of Isotope₂ × Abundance of Isotope₂) + ...
It's important to note that the abundances should be in decimal form (for example, 0.25 for 25% or 25/100), or you can convert percentages to decimals by dividing by 100.
By following this procedure, you can determine the relative atomic mass, which represents the average mass of the atoms of an element, accounting for the different isotopes and their abundances.