Science, Tech, Math › Science S Orbital Definition in Chemistry The Levels of Atomic Structure Share Flipboard Email Print Boris SV / Getty Images Science Chemistry Molecules Basics Chemical Laws 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 June 06, 2018 At any given moment, an electron can be found at any distance from the nucleus and in any direction according to the Heisenberg Uncertainty Principle. The s orbital is a spherically-shaped region describing where an electron can be found, within a certain degree of probability. The shape of the orbital depends on the quantum numbers associated with an energy state. All s orbitals have l = m = 0, but the value of n can vary. S Orbital Versus P Orbital While orbital numbers (e.g., n = 1, 2, 3) indicate the energy level of an electron, the letters (s, p, d, f) describe the orbital shape. The s orbital is a sphere around the atomic nucleus. Within the sphere there are shells in which an electron is more likely to be found at any given time. The smallest sphere is 1s. The 2s orbital is larger than 1s; the 3s orbital is larger than 2s. The p orbital has a dumbell shape and is oriented in a particular direction. At any one energy level, there are three equivalent p orbitals that point at right angles to each other (px, py, pz). As with the s orbital, the p orbital describes a region in space around the nucleus in which an electron may be found with the highest probability.