Science, Tech, Math › Science What Is the Rydberg Formula and How Does It Work? Share Flipboard Email Print ThoughtCo / Nusha Ashjaee 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 Todd Helmenstine Todd Helmenstine is a science writer and illustrator who has taught physics and math at the college level. He holds bachelor's degrees in both physics and mathematics. our editorial process Todd Helmenstine Updated February 06, 2020 The Rydberg formula is a mathematical formula used to predict the wavelength of light resulting from an electron moving between energy levels of an atom. When an electron changes from one atomic orbital to another, the electron's energy changes. When the electron changes from an orbital with high energy to a lower energy state, a photon of light is created. When the electron moves from low energy to a higher energy state, a photon of light is absorbed by the atom. Each element has a distinct spectral fingerprint. When an element's gaseous state is heated, it will give off light. When this light is passed through a prism or diffraction grating, bright lines of different colors can be distinguished. Each element is slightly different from other elements. This discovery was the beginning of the study of spectroscopy. Rydberg's Equation Johannes Rydberg was a Swedish physicist who attempted to find a mathematical relationship between one spectral line and the next of certain elements. He eventually discovered there was an integer relationship between the wavenumbers of successive lines. His findings were combined with Bohr's model of the atom to create this formula: 1/λ = RZ2(1/n12 - 1/n22) where λ is the wavelength of the photon (wavenumber = 1/wavelength) R = Rydberg's constant (1.0973731568539(55) x 107 m-1) Z = atomic number of the atom n1 and n2 are integers where n2 > n1. It was later found that n2 and n1 were related to the principal quantum number or energy quantum number. This formula works very well for transitions between energy levels of a hydrogen atom with only one electron. For atoms with multiple electrons, this formula begins to break down and give incorrect results. The reason for the inaccuracy is that the amount of screening for inner electrons or outer electron transitions varies. The equation is too simplistic to compensate for the differences. The Rydberg formula may be applied to hydrogen to obtain its spectral lines. Setting n1 to 1 and running n2 from 2 to infinity yields the Lyman series. Other spectral series may also be determined: n1 n2 Converges Toward Name 1 2 → ∞ 91.13 nm (ultraviolet) Lyman series 2 3 → ∞ 364.51 nm (visible light) Balmer series 3 4 → ∞ 820.14 nm (infrared) Paschen series 4 5 → ∞ 1458.03 nm (far infrared) Brackett series 5 6 → ∞ 2278.17 nm (far infrared) Pfund series 6 7 → ∞ 3280.56 nm (far infrared Humphreys series For most problems, you'll deal with hydrogen so you can use the formula: 1/λ = RH(1/n12 - 1/n22) where RH is Rydberg's constant, since the Z of hydrogen is 1. Rydberg Formula Worked Example Problem Find the wavelength of the electromagnetic radiation that is emitted from an electron that relaxes from n = 3 to n = 1. To solve the problem, start with the Rydberg equation: 1/λ = R(1/n12 - 1/n22) Now plug in the values, where n1 is 1 and n2 is 3. Use 1.9074 x 107 m-1 for Rydberg's constant: 1/λ = (1.0974 x 107)(1/12 - 1/32) 1/λ = (1.0974 x 107)(1 - 1/9) 1/λ = 9754666.67 m-1 1 = (9754666.67 m-1)λ 1 / 9754666.67 m-1 = λ λ = 1.025 x 10-7 m Note the formula gives a wavelength in meters using this value for Rydberg's constant. You'll often be asked to provide an answer in nanometers or Angstroms. Cite this Article Format mla apa chicago Your Citation Helmenstine, Todd. "What Is the Rydberg Formula and How Does It Work?" ThoughtCo, Aug. 28, 2020, thoughtco.com/what-is-the-rydberg-formula-604285. Helmenstine, Todd. (2020, August 28). What Is the Rydberg Formula and How Does It Work? Retrieved from https://www.thoughtco.com/what-is-the-rydberg-formula-604285 Helmenstine, Todd. "What Is the Rydberg Formula and How Does It Work?" ThoughtCo. https://www.thoughtco.com/what-is-the-rydberg-formula-604285 (accessed September 26, 2021). copy citation Bohr Model of the Atom Explained Bohr Atom Energy Change Example Problem Fluorescence Versus Phosphorescence A to Z Chemistry Dictionary Quantum Numbers and Electron Orbitals Bohr Atom Energy Level How a Photovoltic Cell Works Radiation in Space Gives Clues about the Universe Orbital Definition and Example The Photoelectric Effect S Orbital Definition in Chemistry Photoelectric Effect: Electrons from Matter and Light Antibonding Orbital Definition What Is Blackbody Radiation? A List of Common General Chemistry Problems What Is Chemiluminescence?