This is a list of chemical elements by symbol, including the current signification used to identify the chemical elements as recognized by the International Union of Pure and Applied Chemistry, as well as proposed and historical signs. Also given is each element's atomic number, atomic mass or most stable isotope, group and period numbers on the periodic table, and etymology of the symbol.
NOTE: placing one's cursor over the entry in the etymology column will display a modern English translation for words of Greek, Latin, or other origin.
The following is a list of names formerly used or suggested for use in naming the elements listed above. Also included in this list are placeholder names and names given by discredited claimants for discovery. Names which retain local use (as with aluminum and jod) are not included in this table.
Also called radium emanation, the name was originally given by Friedrich Ernst Dorn in 1900. In 1923, this element officially became radon (the name given at one time to 222Rn, an isotope identified in the decay chain of radium).
The following is a list of pictographic symbols employed to symbolize elements known since ancient times (for example to the alchemists). Not included in this list are symbolic representations of substances previously called elements (such as certain rare earth mineral blends and the classical elementsfire and water of ancient philosophy) which are known today to be multi-atomic. Also not included are symbolic representations currently used for elements in other languages such as the Traditional Chinese elements. Modern alphabetic notation was introduced in 1814 by Jöns Jakob Berzelius.
^ abcdefghijklmnopqrstuvwxyzaaabacadaeafagahaiaj The element does not have any stable nuclides, and a value in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However, three elements, Thorium, Protactinium, and Uranium, have a characteristic terrestrial isotopic composition, and thus their atomic mass given.
^ abcdefghijklmno The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
^ abcdefgh The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
^ The atomic weight of commercial Lithium can vary between 6.939 and 6.996—analysis of the specific material is necessary to find a more accurate value.
The following is a list of isotopes of elements given in the previous tables which have been designated unique symbols. By this it is meant that a comprehensive list of current systematic symbols (in the uAtom form) are not included in the list and can instead be found in the Index to isotope pages chart. Some of the following symbols are no longer in use within the scientific community, however others (most notably some of the named isotopes of hydrogen) continue to be used today. Many of these symbols were designated during the early years of radiochemistry, and several isotopes (namely those in the actinium decay family, the radium decay family, and the thorium decay family) bear placeholder names using the early naming system devised by Ernest Rutherford. Although it is not an isotope, this is perhaps the most useful place to mention that H is the proposed symbol for the only created anti-element, antihydrogen.
From the Greek aktinos. Name restricted at one time to 227Ac, an isotope of actinium. This named isotope later became the official name for element 89.
AcA
Actinium A
84
From actinium and A. Placeholder name given at one time to 215Po, an isotope of polonium identified in the decay chain of actinium.
AcB
Actinium B
82
From actinium and B. Placeholder name given at one time to 211Pb, an isotope of lead identified in the decay chain of actinium.
AcC
Actinium C
83
From actinium and C. Placeholder name given at one time to 211Bi, an isotope of bismuth identified in the decay chain of actinium.
AcC'
Actinium C'
84
From actinium and C'. Placeholder name given at one time to 211Po, an isotope of polonium identified in the decay chain of actinium.
AcC"
Actinium C"
81
From actinium and C". Placeholder name given at one time to 207Tl, an isotope of thallium identified in the decay chain of actinium.
AcK
Actinium K
87
Name given at one time to 223Fr, an isotope of francium identified in the decay chain of actinium.
AcU
Actino-Uranium
92
Name given at one time to 235U, an isotope of uranium.
AcX
Actinium X
88
Name given at one time to 223Ra, an isotope of radium identified in the decay chain of actinium.
From the Greek protos and actinium. Name restricted at one time to 231Pa, an isotope of protactinium. This named isotope later became the official name for element 91.
From radium and emanation. Name restricted at one time to 222Rn, an isotope of radon identified in the decay chain of radium. This named isotope later became the official name for element 86 in 1923.
^ abcdefghijklmnopqrstuvwxyzaaabacadaeafagahaiaj The element does not have any stable nuclides, and a value in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However, three elements, Thorium, Protactinium, and Uranium, have a characteristic terrestrial isotopic composition, and thus their atomic mass given.
^ abcdefghijklmno The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given.
^ abcdefgh The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value.
^ The atomic weight of commercial Lithium can vary between 6.939 and 6.996—analysis of the specific material is necessary to find a more accurate value.
Element name etymologies. Retrieved July 15, 2005.
Atomic Weights of the Elements 2001, Pure Appl. Chem. 75(8), 1107-1122, 2003. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1-109 taken from this source.
IUPAC Standard Atomic Weights Revised (2005).
WebElements Periodic Table. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110-116 taken from this source.
Lapp, Ralph E. Matter. Life Science Library. New York: Time Incorporated. 1963.
Leighton, Robert B. Principles of Modern Physics. New York: McGraw-Hill. 1959.
