0 chemical elements start with J. According to the IUPAC list of 118 recognized elements and authoritative sources such as NIST and PubChem, there is no internationally accepted English element name that begins with the letter J. This absence reflects naming history and language: element names come from Latin or Greek roots, discoverers’ surnames, places, or mythological figures, and the letter J is rare in those classical and modern naming conventions. Note that some languages call iodine “jod,” which can cause confusion, but the official IUPAC English name remains iodine.

Understand the historical and technical reasons behind this gap. The letter J entered scientific alphabets relatively late as a variant of I, and systematic chemical nomenclature followed classical forms and surnames that seldom produced a J initial. Elements are usually named after surnames (for example, gadolinium honors Johan Gadolin but uses his surname Gadolin, producing “Gd” rather than a J name), and IUPAC standards fix a single approved English name for each element, none of which begins with J.

Consult related categories if you expected a J entry. Look at elements beginning with I or at national-language names that contain J (for example, iodine in several European languages). Rely on the Complete Chemical Elements A–Z index built from the IUPAC list for authoritative atomic numbers, standard atomic weights, and discovery years. For the letter J, state plainly: No elements.