What Is a Chemical Element Definition and Examples

An element or chemical element is the simplest form of matter in that it cannot be further broken down using any chemical means. Elements are made up of smaller particles, but you cant take an atom of an element and perform any chemical reaction that will break it apart or join its subunits to make a bigger atom of that element. Atoms of elements may be broken down or fused together using nuclear reactions. Element Basics So far, 118 chemical elements have been found. Of these, 94 are known to occur in nature, while the others are manmade or synthetic elements. Eighty elements have stable isotopes, while 38 are purely radioactive. The most abundant element in the universe is hydrogen: In the Earth (as a whole), its iron. In the Earths crust and the human body, the most abundant element by mass is oxygen. The term element may be used to describe atoms with a given number of protons or any amount of a pure substance made up of atoms of one element. It doesnt matter whether the number of electrons or neutrons varies throughout the sample. What Makes Elements Different From Each Other? How can you tell if two chemicals are the same element? Sometimes examples of a pure element look very different from each other. For example, diamond and graphite (pencil lead) are both examples of the element carbon. You wouldnt know it based on appearance or properties. However, atoms of diamond and graphite each share the same number of protons. The number of protons, particles in an atoms nucleus, determines the element. Elements on the periodic table are arranged in order of increasing numbers of protons. The number of protons is also known as an elements atomic number, which is indicated by the number Z. The reason different forms of an element (called allotropes) can have different properties even though they have the same number of protons is that the atoms are arranged or stacked differently. Think of it in terms of a set of blocks. If you stack the same blocks in different ways, you get different objects. Examples of Elements Pure elements can be found as atoms, molecules, ions, and isotopes. Examples of elements include a hydrogen atom (H), hydrogen gas (H2), the hydrogen ion H, and isotopes of hydrogen (protium, deuterium, and tritium). The element with one proton is hydrogen. Helium contains two protons and is the second element. Lithium has three protons and is the third element, and so on. Hydrogen has the smallest atomic number (1), while the largest known atomic number is that of the recently discovered element oganesson (118). Pure elements contain atoms that all have the same number of protons. If the number of protons of the atoms in a sample is mixed, you have a mixture, called a compound. Examples of pure substances that are not elements include water (H2O), carbon dioxide (CO2) and salt (NaCl). Note how the chemical composition of these materials includes more than one type of atom. If the atoms had been the same type, the substance would have been an element even though it contained multiple atoms. Oxygen gas (O2) and nitrogen gas (N2) are examples of elements. What Is a Chemical Element Definition and Examples A chemical element, or an element, is defined as a material which cannot be broken down or changed into another substance using chemical means. Elements may be thought of as the basic chemical building blocks of matter. There are 118  known elements. Each element is identified according to the number of protons it has in its atomic nucleus. A  new element may be created by adding more protons to an atom. Atoms of the same element have the same atomic number or Z. Key Takeaways: Chemical Element A chemical element is a substance consisting of only one type of atom. In other words, all atoms in an element contain the same number of protons.The identity of a chemical element cannot be changed by any chemical reaction. However, a nuclear reaction can transmute one element into another one.Elements are considered to be the building blocks of matter. This is true, but its worth noting atoms of an element consist of subatomic particles.There are 118 known elements. New elements may yet be synthesized. Element Names and Symbols Each element may be represented by its atomic number or by its element name or symbol. The element symbol is a one or two letter abbreviation. The first letter of an element symbol is always capitalized. A second letter, if it exists, is written in lower case. The International Union of Pure and Applied Chemistry (IUPAC) has agreed on a set of names and symbols for the elements, which are used in scientific literature. However, the names and symbols for the elements may be different in common use in various countries. For example, element 56 is called barium with element symbol Ba by the IUPAC and in English. It is called bario in Italian and baryum in French. Element atomic number 4 is boron to the IUPAC, but boro in Italian, Portuguese, and Spanish, Bor in German, and bore in French. Common element symbols are used by countries with similar alphabets. Element Abundance Of the 118 known elements, 94 are known to occur naturally on Earth. The others are called synthetic elements. The number of neutrons in an element determines its isotope. 80 elements have at least one stable isotope. Thirty-eight  consist solely of radioactive isotopes which decay over time into other elements, which may be either radioactive or stable. On Earth, the most abundant element in the crust is oxygen, while the most abundant element in the entire planet is believed to be iron. In contrast, the most abundant element in the universe is hydrogen, followed by helium. Element Synthesis Atoms of an element may be produced by the processes of fusion, fission, and radioactive decay. All of these are nuclear processes, which means they involve the protons and neutrons in the nucleus of an atom. In contrast, chemical processes (reactions) involve electrons and not nuclei. In fusion, two atomic nuclei fuse to form a heavier element. In fission, heavy atomic nuclei split to form one or more lighter ones. Radioactive decay can produce different isotopes of the same element or a lighter element. When the term chemical element is used, it can refer to a single atom of that atom or to any pure substance consisting only of that type of iron. For example, an iron atom and a bar of iron are both elements of the chemical element. Examples of Elements Element are found on the periodic table. Matter consisting of a single element contains atoms that all have the same number of protons. The number of neutrons and electrons does not impact the identity of an element, so if you had a sample containing protium, deuterium, and tritium (the three isotopes of hydrogen), it would still be a pure element. HydrogenGoldSulfurOxygenUraniumIronArgonAmericiumTritium (an isotope of hydrogen) Examples of Substances That Are Not Elements Substances that are not elements consist of atoms with different numbers of protons. For example, water contains both hydrogen and oxygen atoms. BrassWaterAirPlasticFireSandCarWindowSteel What Makes Elements Different From Each Other? How can you tell if two  chemicals  are the same element? Sometimes examples of a pure element look very different from each other. For example, diamond and graphite (pencil lead) are both examples of the element carbon. You wouldnt know it based on appearance or properties. However, atoms of diamond and graphite each share the same number of protons. The number of protons, particles in an atoms nucleus, determines the element. Elements on the  periodic table  are arranged in order of increasing numbers of protons. The number of protons is also known as an elements atomic number, which is indicated by the number Z. The reason different forms of an element (called allotropes) can have different properties even though they have the same number of protons is that the atoms are arranged or stacked differently. Think of it in terms of a set of blocks. If you stack the same blocks in different ways, you get different objects. Sources E. M. Burbidge; G. R. Burbidge; W. A. Fowler; F. Hoyle (1957). Synthesis of the Elements in Stars. Reviews of Modern Physics. 29 (4): 547–650. doi:10.1103/RevModPhys.29.547Earnshaw, A.; Greenwood, N. (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann.