The atomic mass of the element concerned must be divided by the number of valence ions present in that element. The number of ions is calculated by multiplying the valence value of the element by the mass in milligrams of the element in question.
- Establish the number of valence ions available
Each element has its own valence value. Aluminum, for example, has a valence value of 3, often represented as Al 3+. Consulting a table of valence values assists in this process. To find the number of ions in 10mg of aluminum, 10mg is multiplied by the valence value of 3 to give an answer of 30 ions.
- Find the atomic mass of the element in question
The atomic mass of an element can be found by consulting the periodic table. In this example, the atomic mass of aluminum is 27.
- Divide the atomic mass by the number of valence ions
Calculate the milliequivalents by dividing the atomic number by the number of valence ions. Here, 27 divided by 30 gives 0.9 milliequivalents in 10mg of aluminum.