In summary, a naturally occurring element is one that has at least one isotope that can be found in nature or on Earth. The number of naturally occurring elements observed is 88, 90, 92, 93, 94, and 98, with the atomic number range from 1 to 92. However, there are exceptions such as Technetium and Promethium, which can also be found in nature through radioactive decay. Lead is the last completely stable element, while Bismuth and Polonium are also considered naturally occurring on Earth. Astatine, on the other hand, is the rarest naturally occurring element in the Earth's crust. "Nature" in scientific terminology refers to the universe, including all