Science, Tech, Math › Science What Are the First 20 Elements? Share Flipboard Email Print ThoughtCo. Science Chemistry Periodic Table Basics Chemical Laws Molecules 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 February 05, 2020 One common chemistry assignment is to name or even memorize the first 20 elements and their symbols. The elements are ordered in the periodic table according to increasing atomic number. This is also the number of protons in each atom. These are the first 20 elements, listed in order: H - HydrogenHe - HeliumLi - LithiumBe - BerylliumB - BoronC - CarbonN - NitrogenO - OxygenF - FluorineNe - NeonNa - SodiumMg - MagnesiumAl - AluminumSi - SiliconP - PhosphorusS - SulfurCl - ChlorineAr - ArgonK - PotassiumCa - Calcium Element Symbols and Numbers The number of the element is its atomic number, which is the number of protons in each atom of that element. The element symbol is a one- or two-letter abbreviation of the element's name. Sometimes it refers to an old name. (For instance, K is for kalium.) The element name can tell you something about its properties. Elements with names ending with -gen are nonmetals that are gases in pure form at room temperature.Elements that have names ending with -ine belong to a group of elements called halogens. Halogens are extremely reactive and readily form compounds.Element names ending with -on are noble gases, which are inert or nonreactive gases at room temperature.Most element names end with -ium. These elements are metals, which are usually hard, shiny, and conductive. What you cannot tell from an element name or symbol is how many neutrons or electrons an atom possesses. To know the number of neutrons, you need to know the isotope of the element. This is indicated using numbers (superscripts, subscripts, or following the symbol) to give the total number of protons and neutrons. For example, carbon-14 has 14 protons and neutrons. Since you know all atoms of carbon have 6 protons, the number of neutrons is 14 - 6 = 8. Ions are atoms that have different numbers of protons and electrons. Ions indicated using a superscript after the element symbol that states whether the charge on the atom is positive (more protons) or negative (more electrons) and the quantity of the charge. For example, Ca2+ is the symbol for a calcium ion that has a positive 2 charge. Since the atomic number of calcium is 20 and the charge is positive, this means the ion has 20 - 2 or 18 electrons. Chemical Elements To be an element, a substance has to at least have protons, since these particles define the type of element. Elements consist of atoms, which contain a nucleus of protons and neutrons surrounded by a cloud or shell of electrons. Elements are considered the basic building blocks of matter because they are the simplest form of matter that cannot be divided using any chemical means. Learn More Knowing the first 20 elements is a good way to start learning about elements and the periodic table. Next, review the full element list and learn how to memorize the first 20 elements. Once you feel comfortable with the elements, test yourself by taking the 20 element symbol quiz.