Svante August Arrhenius (19 February 1859–2 October 1927) was a Swedish scientist, originally a physicist, but often referred to as a chemist, and one of the founders of the science of physical chemistry.

At the University of Uppsala, he was unsatisfied with the chief instructor of physics and the only faculty member who could have supervised him in chemistry, Per Teodor Cleve, so he left to study at the Physical Institute of the Swedish Academy of Sciences in Stockholm under the physicist Erik Edlund in 1881.
In 1884, based on this work, he submitted a 150-page dissertation on electrolytic conductivity to Uppsala for the doctorate.
In 1889 Arrhenius explained the fact that most reactions require added heat energy to proceed by formulating the concept of activation energy, an energy barrier that must be overcome before two molecules will react.
In 1891 he became a lecturer at the Stockholm University College , being promoted to professor of physics in 1895, and rector in 1896.
About 1900, Arrhenius became involved in setting up the Nobel Institutes and the Nobel Prizes.
He was elected a member of the Royal Swedish Academy of Sciences in 1901.
In 1905, upon the founding of the Nobel Institute for Physical Research at Stockholm, he was appointed rector of the institute, the position where he remained until retirement in 1927.
In September, 1927, he came down with an attack of acute intestinal catarrh, died on 2 October, and was buried in Uppsala.