Science, Tech, Math › Science Electron Configuration Definition Share Flipboard Email Print Guido Mieth / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated December 09, 2019 Electron configuration refers to the populations of electronic energy sublevels of an atom. The electronic configuration notations for all of the elements are available in one chart. Example The electronic configuration of a lithium atom is 1s22s, which indicates there are two electrons in the 1s sublevel and one electron in the 2s energy sublevel.