For example, hydrogen is a colorless gas, carbon as charcoal, graphite or coke is black, sulfur powder is yellow, chlorine is a greenish gas, bromine is a dark red liquid, iodine in ether is violet, amorphous phosphorus is red, rust is dark orange-red, etc. Several of the CPK colors refer mnemonically to colors of the pure elements or notable compound. Light, medium, medium dark, and dark green for the halogens ( F, Cl, Br, I)ДЄ box of ball-and-stick model pieces colored to represent several of the common elements.ДЄlkaline earth metals ( Be, Mg, Ca, Sr, Ba, Ra).In his patent he mentions the following colors: In 1965 Koltun patented an improved version of the Corey and Pauling modeling technique. They also built smaller models using plastic balls with the same color schema. Their models represented atoms by faceted hardwood balls, painted in different bright colors to indicate the respective chemical elements. In 1952, Corey and Pauling published a description of space-filling models of proteins and other biomolecules that they had been building at Caltech. Hofmann's original colour scheme ( carbon = black, hydrogen = white, nitrogen = blue, oxygen = red, chlorine = green, and sulphur = yellow) has evolved into the later color schemes.

At a Friday Evening Discourse at London's Royal Institution on April 7, 1865, he displayed molecular models of simple organic substances such as methane, ethane, and methyl chloride, which he had had constructed from differently colored table croquet balls connected together with thin brass tubes. August Wilhelm von Hofmann was apparently the first to introduce molecular models into organic chemistry, following August Kekule's introduction of the theory of chemical structure in 1858, and Alexander Crum Brown's introduction of printed structural formulas in 1861.

Periodic table color coded