Element Quiz: Test Your Knowledge of Avatar Chemical Elements

Species of Atoms with a Specific Number of Protons

A chemical element is a substance that cannot be broken down into other substances and is distinguished by the number of protons in the nuclei of its atoms, known as its atomic number.
The majority of baryonic matter in the universe is composed of chemical elements, and they undergo chemical reactions to form new compounds.
Dmitri Mendeleev published the first recognizable periodic table in 1869, which organizes the elements by increasing atomic number into rows and columns based on recurring physical and chemical properties.
The International Union of Pure and Applied Chemistry has recognized a total of 118 elements, with the first 94 occurring naturally on Earth and the remaining 24 being synthetic elements produced in nuclear reactions.
The lightest chemical elements, hydrogen, and helium were created by Big Bang nucleosynthesis, and almost all other elements found in nature were made by various natural methods of nucleosynthesis.
Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope, and elements with atomic numbers 83 through 94 are unstable.
Isotopes are atoms of the same element but having different numbers of neutrons, and most naturally occurring elements have more than one stable isotope.
The mass number of an element is the number of nucleons in the atomic nucleus, and the atomic mass of a single atom is a real number giving the mass of a particular isotope of the element.
The standard atomic weight of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit.
Chemists and nuclear scientists have different definitions of a pure element, with chemists considering a pure element to be a substance whose atoms all (or almost all) have the same atomic number and nuclear scientists defining a pure element as one that consists of only one stable isotope.
Atoms of chemically pure elements may bond to each other in more than one way, allowing the pure element to exist in multiple chemical structures, known as allotropes, which differ in their properties.
The reference state of an element is defined by convention, usually as the thermodynamically most stable allotrope and physical state at a given temperature and pressure.
Descriptive categorizations can be applied broadly to the elements, including consideration of their general physical and chemical properties, their states of matter, their melting and boiling points, their densities, their crystal structures as solids, and their origins.Classification and Properties of Chemical Elements
Chemical elements can be classified as metals, nonmetals, and metalloids based on their physical and chemical properties.
The periodic table categorizes elements into groups such as alkali metals, alkaline earth metals, halogens, transition metals, post-transition metals, metalloids, reactive nonmetals, and noble gases.
The state of matter (solid, liquid, or gas) of an element at standard temperature and pressure (STP) can be used to categorize elements.
Melting and boiling points, densities, and crystal structures are also important properties that are used to characterize elements.
The origin of elements on Earth can be categorized as naturally occurring or synthetic, with naturally occurring elements further divided into primordial and transient elements.
The periodic table provides a powerful framework for organizing and comparing the properties of elements, with 118 confirmed elements as of 2021.
Chemical elements are identified by their unique atomic numbers, accepted names, and symbols.
The names of elements were given locally by various cultures before the atomic theory of matter, and national differences emerged over the names of elements.
The International Union of Pure and Applied Chemistry (IUPAC) decides on the official names of chemical elements, drawing on traditional English names for international communication and trade.
Chemical symbols are capitalized and consist of letters of the Latin alphabet, with the first letter always capitalized and subsequent letters always lowercase.
There are also symbols in chemical equations for groups of chemical elements, such as "X" for variable groups and "R" for radicals.
Chemical symbols are intended as universal symbols for people of all languages and alphabets.Overview of Chemical Elements
Chemical elements are substances made up of only one type of atom, characterized by their atomic number (number of protons in the nucleus).
The periodic table of elements organizes the 118 known chemical elements by their atomic structure, electron configurations, and chemical properties.
In addition to their standard abbreviations, some elements have alternative two-letter symbols, such as "Ln" for lanthanides and "An" for actinides.
Isotopes are variations of an element that differ in the number of neutrons in the nucleus, and are designated by the atomic mass number combined with the element's symbol.
The vast majority of the universe's matter is dark matter, which does not consist of atoms or chemical elements.
The 94 naturally occurring chemical elements were produced by at least four astrophysical processes, including Big Bang nucleosynthesis, stellar nucleosynthesis, explosive nucleosynthesis, and cosmic ray spallation.
Only hydrogen-1, helium-4, and trace amounts of lithium and beryllium were produced in the Big Bang, with heavier elements produced by subsequent astrophysical processes.
The relative abundances of elements on Earth and in the universe reflect their formation history, with lighter elements more abundant in the former and heavier elements more abundant in the latter.
The definition of an element has evolved over time, from classical definitions based on the ancient Greek elements, to chemical definitions based on pure substances, to atomic definitions based on atomic number.
The discovery of chemical elements has occurred throughout human history, with most naturally occurring elements identified and characterized by 1900.
Since 1999, new element discoveries have been confirmed by the International Union of Pure and Applied Chemistry (IUPAC), with all 118 currently known elements having been discovered and named.