How Do You Calculate Relative Atomic Mass?
Relative atomic mass is an important aspect for each element in the periodic table. The relative atomic mass of an element looks considers each unique isotope for an element and its natural abundance on earth. The relative atomic mass for elements is the number that is displayed below the element on the period table. Step 1 Determine how many isotopes exist for the element. For example, magnesium has three isotopes: magnesium-24, magnesium-25 and magnesium-26. Step 2 Find out the mass (in amu) of every isotope of the element. For magnesium, the mass for each isotope is: magnesium-24 – 23.985 amu magnesium-25 – 24.986 amu magnesium-26 – 25.983 amu. Step 3 Look up the natural abundance of each isotope. For magnesium’s isotopes, this would be: magnesium-24 – 78.99 percent magnesium25 -10.00 percent magnesium-26 – 11.01 percent Step 4 Add each isotope’s mass multiplied by the percentage of the isotopes natural abundance together. So magnesium’s relative atomic mass is: 23.985*.7899+ 24.986
Relative atomic mass is an important aspect for each element in the periodic table. The relative atomic mass of an element looks considers each unique isotope for an element and its natural abundance on earth. The relative atomic mass for elements is the number that is displayed below the element on the period table. Determine how many isotopes exist for the element. For example, magnesium has three isotopes: magnesium-24, magnesium-25 and magnesium-26. Find out the mass (in amu) of every isotope of the element. For magnesium, the mass for each isotope is: magnesium-24 – 23.985 amu magnesium-25 – 24.986 amu magnesium-26 – 25.983 amu. Look up the natural abundance of each isotope. For magnesium’s isotopes, this would be: magnesium-24 – 78.99 percent magnesium25 -10.00 percent magnesium-26 – 11.01 percent Add each isotope’s mass multiplied by the percentage of the isotopes natural abundance together. So magnesium’s relative atomic mass is: 23.985*.7899+ 24.986*.1+25,983*.1101 = 24.31 amu
