Using the Periodic table of Elements


While the Periodic Table of Elements is a fixture in high school and university chemistry labs, it also remains a common reference long after the school years. Cole-Parmer resident chemistry expert James Lindlof explained, “Most users reference the table to find the atomic weights of elements. The atomic weights are used in the calculation of molarity and normality, which are standard units used by chemists.”

The molar concentration is the number of moles of substances divided by the volume (L) of the solution. This is an easy calculation once the atomic weight of the constituent elements of the molecules is known. The molar mass of the element is the atomic or molecular weight expressed in grams per mole. A typical expression of this calculation would be moles of solute per liter of solution: (mol/L=m)

“Molarity is easier to use than percentages,” said Lindlof. “In analytical processes or process chemistry, these calculations can be determined by facilities that don’t have a titrator. For example, smaller facilities performing research and development or conducting quality assurance and quality control may refer to the Periodic Table to make their calculations rather than investing in more expensive equipment.”

The position of the element on the table also indicates the quantum shells or electron mass of the element, also referred to as the principle energy level. “Most electronically dense atoms are to the top right of the table, as you move down to the left the electron density decreases,” said Lindlof. “Very simply, this can allude to the effective hydrated radius, which will affect ionic interactions and solubilities within a solution.”

Click here to view a larger image of the Periodic Table of Elements.

Periodic Table of the Elements