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The number of natural elements on the periodic table is debated, with some considering elements 93 and 94 as natural. Unstable isotopes and short half-lives make some elements rare. Four elements, technetium, promethium, astatine, and francium, are questionable. The number of natural elements ranges from 88 to 92, depending on which elements are included. Natural does not necessarily mean abundant.
The answer to the question of how many objects on the periodic table of elements occur in nature is actually a bit complicated. Conventional wisdom says that the first 92 elements, from element 1, hydrogen, to element 92, uranium, all occur in nature, but in reality some of these elements are highly unstable and have only been observed when they were created artificially. Some people believe that elements 93 (neptunium) and 94 (plutonium) should also be included in a list of natural elements. As a result, anywhere between 94 and 88 elements are “natural,” depending on which definition you’re using.
Elements are considered “natural” when they can be found in nature, rather than needing to be created in a laboratory, and many representations of the periodic table of elements include a dividing line between natural and man-made elements. Some natural elements have very unstable isotopes or short half-lives, so they exist only intermittently and in very small quantities on Earth. Some people believe that when one thinks of the periodic table, elements like these shouldn’t be considered “natural,” especially since they’re only observed as a direct result of human activity. Others argue that while only small amounts are observable at any given time, they are “natural” because they can occur spontaneously.
The questionable elements are element 43, technetium; element 61, promethium; element 85, astatine; and element 87, francium. Elements 43 and 61 are somewhat unusual, as they are surrounded by stable elements, but have only been observed under controlled laboratory conditions. Elements 85 and 87 appear in nature, but only briefly and very rarely, which makes it difficult to pin down a true natural appearance for these shy elements.
If all four questionable elements are dropped from the list of “natural” elements, there are 90 or 88 naturally occurring elements, depending on whether neptunium and plutonium are included in the list or not. Some people also include astatine and francium, bringing the total to 92 or 90. The most commonly cited number is “92,” which could be seen as the first 92 entries in the periodic table, or the first 94 minus elements 43 and 61, a depending on how complicated people feel.
It’s important for people to remember that, when looking at the periodic table of elements, “naturally” doesn’t necessarily mean “abundant.” Many naturally occurring elements are in fact quite rare, although some were once again abundant. Element levels also change depending on where a person is; helium, for example, is rare on Earth but abundant around the Sun.
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