Both neptunium and plutonium can be detected in uranium minerals, though the amounts are small. Uranium minerals regularly contain 1.8 microgrammes of neptunium and up to 0.15 microgrammes of plutonium per ton uranium. In addition there is also primeval plutonium on Earth. The isotope 244 has a half-life of 82.6 million years, and this is enough that a minute amount has survived since the elements making up the Earth were created in the last supernova event before the birth of the solar system.
https://www.quora.com/How-many-naturally-occuring-chemical-elements-are-there-on-Earth
If all four questionable elements are struck from the list of “naturally occurring” elements, there are either 90 or 88 naturally occurring elements, depending on whether or not neptunium and plutonium are included on the list. Some people include astatine and francium as well, raising the total to 92 or 90. The most-commonly cited number is “92,” which could be viewed as the first 92 entries on the periodic table, or the first 94 minus elements 43 and 61, depending on how complicated people feel like being.
http://www.wisegeek.org/how-many-elements-on-the-periodic-table-of-the-elements-occur-naturally.htm
All chemical elements up to chemical element number 92, uranium, have been found naturally on earth with the exception of Technetium, atomic number 43. All elements above atomic number 92 are man made. Written Aug 16, 2015.
https://www.quora.com/How-many-naturally-occuring-chemical-elements-are-there-on-Earth
exists and is an alternate of . Ninety elements occur naturally. They are any elements with an atomic number of 92 or less, excluding technetium (43) and promethium (61). Ninety elements occur naturally. They are any elements with an atomic number of 92 or less, excluding technetium (43) and promethium (61).
http://www.answers.com/Q/How_many_element_occur_naturally_on_Earth
The answer to the question of how many objects on the periodic table of the elements are naturally occurring is actually a bit complicated.
http://www.wisegeek.org/how-many-elements-on-the-periodic-table-of-the-elements-occur-naturally.htm
Some people believe that elements 93 (neptunium) and 94 (plutonium) should also be included on a list of naturally occurring elements. As a result, anywhere between 94 and 88 elements are “naturally occurring,” depending on the definition one is using.
http://www.wisegeek.org/how-many-elements-on-the-periodic-table-of-the-elements-occur-naturally.htm
According to sources, Astatine (At) is the rarest naturally occurring element, roughy 25 grams are in the earth's crust at any given time. It has a half-life of only 8.3 hours…. (MORE) 4 people found this useful.
http://www.answers.com/Q/How_many_element_occur_naturally_on_Earth
Naturally-Occurring and Synthetic Elements. Elements 1 through 92 (except for elements 43 and 61) occur naturally on Earth, although some are only present in extremely small quantities. Element 43, Technetium (Tc), is unstable, and all of its isotopes have relatively short half-lives, ranging from 4.2 million years (98Tc) to 5.0 seconds (108Tc).
https://www.angelo.edu/faculty/kboudrea/periodic/physical_natural.htm
Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium, atomic number 43; promethium, number 61; astatine, number 85; francium, number 87; neptunium, number 93; and plutonium, number 94.
https://en.wikipedia.org/wiki/Chemical_element
Element 61, Promethium (Pm), is also unstable. The most stable isotope of the element, promethium-145, has a half-life of 17.7 years; promethium-146 has a half-life of only 5.53 years, while that of promethium-147 is 2.62 years. There are a number of other isotopes as well, but the majority of them have half-lives that are less than 30 seconds.
https://www.angelo.edu/faculty/kboudrea/periodic/physical_natural.htm
how many elements occur naturally on earth
There are 92 elements occur naturally on earth. 92 elements occur naturally on Earth.