Which major areas of chemistry did Gilbert N. Lewis contribute to?

Gilbert N. Lewis was a prominent American physical chemist who made foundational contributions across several major areas of chemistry:

• Chemical Thermodynamics: Lewis focused on bridging the gap between thermodynamic theory and practical application. He introduced key concepts such as fugacity, activity coefficient, and ionic strength to describe the behavior of real gases and solutions.1
• Chemical Bonding: He developed the electron-pair model of the covalent bond, famously introducing Lewis structures (electron dot diagrams) to represent the electronic structures of atoms and molecules.23
• Acid-Base Theory: He introduced the Lewis theory, which defines an acid as an electron-pair acceptor and a base as an electron-pair donor.43
• Other Research: Lewis also conducted significant work on the separation and study of deuterium and its compounds, as well as research into phosphorescence and the triplet state.3