First of all, let's realize what the term "not naturally occurring" means. The natural abundance of 85-Astatium is estimated to be around 10-24 %, which gives the content of this element on Earth around 600g of At in the whole Earth. And keep in mind, that the most stable isotope, At-210, has a half-life of eight hours. So it is reasonable to say that it is not existing naturally. --- The most widely accepted list of artificial elements includes: 43-Technetium, 61-Prometium. The traces of elements 85, 87, 93 and even 94 were found in nature, as these are by-products of the natural decay of uranium or thorium. Generally we say these don't occur naturally, because their content is within the range of 10-10 % to 10-16 %. All elements heavier than plutonium (atomic number 95 and higher) don't exist as Natural Resources of our planet. The elements 84, 86, 88, 89, 91 are sometimes treated as natural or artificial - depends on the criteria used. --- If we take into account the elements which were DISCOVERED in the nuclear research centers and not extracted from the natural minerals, we get: 43, 61, 85, 93 and above.
First of all, let's realize what the term "not naturally occurring" means. The natural abundance of 85-Astatium is estimated to be around 10-24 %, which gives the content of this element on Earth around 600g of At in the whole Earth. And keep in mind, that the most stable isotope, At-210, has a half-life of eight hours. So it is reasonable to say that it is not existing naturally. --- The most widely accepted list of artificial elements includes: 43-Technetium, 61-Prometium. The traces of elements 85, 87, 93 and even 94 were found in nature, as these are by-products of the natural decay of uranium or thorium. Generally we say these don't occur naturally, because their content is within the range of 10-10 % to 10-16 %. All elements heavier than plutonium (atomic number 95 and higher) don't exist as Natural Resources of our planet. The elements 84, 86, 88, 89, 91 are sometimes treated as natural or artificial - depends on the criteria used. --- If we take into account the elements which were DISCOVERED in the nuclear research centers and not extracted from the natural minerals, we get: 43, 61, 85, 93 and above.
Any element with an atomic number of 95 or more does not occur naturally on Earth. In addition, the elements technetium and promethium do not occur often enough, and are included in those that don't occur naturally. See the related link for a list of naturally existing and synthetic elements, and explanations for why this is so.
89 elements are considered to occur naturally the others are not,the question is how many elements are 'known' up till now?
Most people think it to be about 120.
Naturally occurring elements (89) in alphbetical order:
"actinium", "aluminum", "antimony", "argon", "arsenic", "barium", "beryllium", "bismuth", "boron", "bromine", "cadmium", "calcium", "carbon", "cerium", "cesium", "chlorine", "chromium", "cobalt", "copper", "dysprosium", "erbium", "europium", "fluorine", "francium", "gadolinium", "gallium", "germanium", "gold", "hafnium", "helium", "holmium", "hydrogen", "indium", "iodine", "iridium", "iron", "krypton", "lanthanum", "lead", "lithium", "Lutetium", "Magnesium", "Manganese", "Mercury", "Molybdenum", "Neodymium", "Neon", "Nickel", "Niobium", "Nitrogen", "Osmium", "Oxygen", "Palladium", "Phosphorus", "Platinum", "Polonium", "Potassium", "Praseodymium", "Protactinium", "Radium", "Radon", "Rhenium", "Rhodium", "Rubidium", "Ruthenium", "Samarium", "Scandium", "Selenium", "Silicon", "Silver", "Sodium", "Strontium", "Sulfur", "Tantalum", "Tellurium", "Terbium", "Thallium", "Thorium", "Thulium", "Tin", "Titanium", "Tungsten", "Uranium", "Vanadium", "Xenon", "Ytterbium", "Yttrium", "Zinc", "Zirconium"
Because it is intended to represent all known elements, not only those which exist in nature.
There are 92 naturally occurring elements, with a total of 118 naturally occurring elements in the periodic table. Each element is composed of atoms with a specific number of protons in the nucleus that determines its identity.
Not all the elements occur naturally; some elements are man-made.
Different elements have between 0 and 10 naturally occurring isotopes, and between about 3 and 25 if you also include artificially prepared and characterized ones.
Atomic mass.
There are 90 elements that exist naturally.
Mineralogists call an element that occurs naturally in its pure form uncombined with other elements a native element. These elements are typically found in nature in their pure metallic form, such as gold, silver, and copper.
Because it is intended to represent all known elements, not only those which exist in nature.
No - not naturally, it usually exist with other elements. To achieve a pure form, MnO2 needs to be heated with carbon to remove the oxygen.
All are radioactive, artificial elements (but note that Np and Pu can exist also naturally in extremely low concentrations).
Most of the naturally occurring elements are metals. These elements are found in the Earth's crust and have various physical and chemical properties. Some examples of naturally occurring metals include iron, copper, and gold.
The 11 elements that naturally exist as gases at room temperature and pressure are hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon, and radon.
Some elements do not naturally occur as diatomic molecules, such as helium, neon, argon, krypton, and xenon. These elements exist as monatomic gases because they are stable in their single atom form due to having a full valence electron shell.
Many elements exist naturally in more than one isotopic form, each of which has a different atomic mass number. However, all of these isotopes have almost identical chemical properties, and it is therefore more useful to chemists to list elements in the table, along with the average atomic mass resulting from any mixture of isotopes that naturally occurs.
There are 92 naturally occurring elements, with a total of 118 naturally occurring elements in the periodic table. Each element is composed of atoms with a specific number of protons in the nucleus that determines its identity.
Minerals are inorganic or nonliving elements that exist naturally on Earth and are present in all rocks. Minerals have a specific chemical composition and crystal structure.
Not all the elements occur naturally; some elements are man-made.