Science, Tech, Math › Science What Is Valence or Valency? The terms have two related meanings in chemistry Share Flipboard Email Print Valence is a measure of how readily an atom or radical forms a bond. Jason Reed / Getty Images Science Chemistry Physical Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry 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. Anne Marie Helmenstine, Ph.D. Facebook Twitter 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. Learn about our Editorial Process Updated on September 30, 2018 The words valence and valency have two related meanings in chemistry. Valence describes how easily an atom or radical can combine with other chemical species. This is determined based on the number of electrons that would be added, lost, or shared if it reacts with other atoms. Valence is denoted using a positive or negative integer used to represent this binding capacity. For example, common valences of copper are 1 and 2. Table of Element Valences Number Element Valence 1 Hydrogen (-1), +1 2 Helium 0 3 Lithium +1 4 Beryllium +2 5 Boron -3, +3 6 Carbon (+2), +4 7 Nitrogen -3, -2, -1, (+1), +2, +3, +4, +5 8 Oxygen -2 9 Fluorine -1, (+1) 10 Neon 0 11 Sodium +1 12 Magnesium +2 13 Aluminum +3 14 Silicon -4, (+2), +4 15 Phosphorus -3, +1, +3, +5 16 Sulfur -2, +2, +4, +6 17 Chlorine -1, +1, (+2), +3, (+4), +5, +7 18 Argon 0 19 Potassium +1 20 Calcium +2 21 Scandium +3 22 Titanium +2, +3, +4 23 Vanadium +2, +3, +4, +5 24 Chromium +2, +3, +6 25 Manganese +2, (+3), +4, (+6), +7 26 Iron +2, +3, (+4), (+6) 27 Cobalt +2, +3, (+4) 28 Nickel (+1), +2, (+3), (+4) 29 Copper +1, +2, (+3) 30 Zinc +2 31 Gallium (+2). +3 32 Germanium -4, +2, +4 33 Arsenic -3, (+2), +3, +5 34 Selenium -2, (+2), +4, +6 35 Bromine -1, +1, (+3), (+4), +5 36 Krypton 0 37 Rubidium +1 38 Strontium +2 39 Yttrium +3 40 Zirconium (+2), (+3), +4 41 Niobium (+2), +3, (+4), +5 42 Molybdenum (+2), +3, (+4), (+5), +6 43 Technetium +6 44 Ruthenium (+2), +3, +4, (+6), (+7), +8 45 Rhodium (+2), (+3), +4, (+6) 46 Palladium +2, +4, (+6) 47 Silver +1, (+2), (+3) 48 Cadmium (+1), +2 49 Indium (+1), (+2), +3 50 Tin +2, +4 51 Antimony -3, +3, (+4), +5 52 Tellurium -2, (+2), +4, +6 53 Iodine -1, +1, (+3), (+4), +5, +7 54 Xenon 0 55 Cesium +1 56 Barium +2 57 Lanthanum +3 58 Cerium +3, +4 59 Praseodymium +3 60 Neodymium +3, +4 61 Promethium +3 62 Samarium (+2), +3 63 Europium (+2), +3 64 Gadolinium +3 65 Terbium +3, +4 66 Dysprosium +3 67 Holmium +3 68 Erbium +3 69 Thulium (+2), +3 70 Ytterbium (+2), +3 71 Lutetium +3 72 Hafnium +4 73 Tantalum (+3), (+4), +5 74 Tungsten (+2), (+3), (+4), (+5), +6 75 Rhenium (-1), (+1), +2, (+3), +4, (+5), +6, +7 76 Osmium (+2), +3, +4, +6, +8 77 Iridium (+1), (+2), +3, +4, +6 78 Platinum (+1), +2, (+3), +4, +6 79 Gold +1, (+2), +3 80 Mercury +1, +2 81 Thallium +1, (+2), +3 82 Lead +2, +4 83 Bismuth (-3), (+2), +3, (+4), (+5) 84 Polonium (-2), +2, +4, (+6) 85 Astatine ? 86 Radon 0 87 Francium ? 88 Radium +2 89 Actinium +3 90 Thorium +4 91 Protactinium +5 92 Uranium (+2), +3, +4, (+5), +6 Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "What Is Valence or Valency?" ThoughtCo, Aug. 27, 2020, thoughtco.com/what-is-valence-or-valency-606459. Helmenstine, Anne Marie, Ph.D. (2020, August 27). What Is Valence or Valency? Retrieved from https://www.thoughtco.com/what-is-valence-or-valency-606459 Helmenstine, Anne Marie, Ph.D. "What Is Valence or Valency?" ThoughtCo. https://www.thoughtco.com/what-is-valence-or-valency-606459 (accessed May 29, 2023). copy citation Featured Video By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies