Which elements are called transactinoids?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — transuranium element Modern version of the periodic table of the elements (printable).

The term transactinoids refers to the chemical elements with atomic numbers greater than 103, which follow the actinoid series in the periodic table.1

These elements are a subset of the transuranium elements, which include all elements with atomic numbers greater than 92. While the actinoid series encompasses elements 89 through 103, the transactinoids begin with element 104, rutherfordium. Other identified transactinoids include dubnium (105), seaborgium (106), bohrium (107), hassium (108), nihonium (113), and flerovium (114).123

Because these elements are highly unstable and typically possess very short half-lives, scientists rely on theoretical calculations and specialized "fast chemistry" techniques to study their properties and determine their placement within the periodic table.124