How are isotopes formed?
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Isotopes are forms of an element whose nuclei have the same atomic number–-the number of protons in the nucleus--but different mass numbers because they contain different numbers of neutrons.\n\nThe word isotope, meaning at the same place, comes from the fact that all isotopes of an element are located at the same place on the periodic table.\n\nCollectively, the isotopes of the elements form the set of nuclides. A nuclide is a particular type of atomic nucleus, or more generally an agglomeration of protons and neutrons. Strictly speaking, it is more correct to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope.\n\nIn scientific nomenclature, isotopes (nuclides) are specified by the name of the particular element by a hyphen and the number of nucleons (protons and neutrons) in the atomic nucleus (e.g., helium-3, carbon-12, carbon-14, iron-57, uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g., 3He, 12C, 14C, 57Fe, 238U).\n\nSee link below for more info.
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cations form when the atoms lose an electron or more and have + valency , so the mass will decrease and the effect of the nuclei on the remaining electrons will be stronger so it attracts them stronger toward the center so the size will decrease .. while in the anions the number of electrons increase so the attraction caused by the nuclei is weaker so the size is larger ..\n\nsize of the cation of an element < size of the atom of that element < size of the anion of that element
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A carbon atom is one that has 6 proton in the nucleus. If it is uncharged, there will also be 6 electrons. The number of neutrons varies depending on the isotope. The most common isotope has 6 neutrons. There is another stable isotope with 7 neutrons and a radioactive one with 8.
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Most of the naturally occuring stuff comes from unstable atoms.  When the balance between protrons and neutrons is out of whack, the atom will fly apart.  Depending on the atom, it will break apart in one of 3 ways, it will emit an electron (beta decay), part of the nucleus (alpha) or throw off an electromagnetic wave (gamma). \nGamma also commonly comes from high energy particle hitting the atmosphere and shattering atoms.  The interaction releases a shower of other particles some of which release gamma.  It's nothing to worry about as we evolved under these conditions and our bodies are build to handle it.
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A chemical reaction involves only the electrons of the atoms -- the nucleus of each atom remains unchanged.  In addition, the same number of the same types of atoms is present after the reaction as was present before the reaction.\n\nA nuclear reaction involves a change of the nucleus of the atom(s), either splitting one large nucleus into one or more smaller nuclei (fission) or joining multiple nuclei together to form a larger nucleus (fusion).  This means that after a nuclear reaction, there are a different number of different types of atoms than there were before the nuclear reaction.\n\nIn addition, nuclear reaction tends to produce large amounts of high-energy photons (x-rays, gamma rays, etc) and nuclear particles (alpha and beta particles) as a result of the reaction.  Chemical reactions produce low-energy photons (heat and visible light) and do not produce nuclear particles.\n\nIn a nuclear reaction, some of the matter of the original atom is converted into energy -- so the resulting products will have less mass than the total mass of all the original material.  In a chemical reaction, the mass always remains the same because the same number and type of atoms are still present.
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kiki is right, and most other answers wrong. 'Decay' is only applied to radioactive elements, and not all elements are radioactive. Many have *isotopes* that are radioactive, but aren't the stable form of the element. For example, carbon 14 is radioactive carbon and decays; Carbon 13, the stable version, will never do so. \n\nStable elements can go through fusion or fission, effectively changing them into something else (for example, carbon fuses at about 600 million degrees K), but that is *not* decay, since decay involves *spontaneous* emission of radiation, and that event only involves external factors, like a star exploding, and is not a property of the element - so, again, that can't be called 'decay'.\n\nSo, no, not all elements decay over time, only the ones that have no stable isotope - all elements above 83, bismuth.
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Isotopes are atoms with the same amount of protons, but different numbers of neutrons.
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Actually, iron is just the heaviest element that can be formed through a thermodynamically favorable fusion reaction.  Larger nuclei can be formed through fusion it just that the reaction consumes energy that rather than releasing it.  Fusion of larger nuclei can occur in supernovas basically because there is enough energy floating around in there (in the form of heat) to cause thermodynamically unfavorable nuclear reactions (i.e. fusion resulting in nuclei larger than iron) to occur.
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Isomers are molecules with the same chemical formula but different structures.  Isotopes are atoms of the same element but have different numbers of neutrons.  The right one for carbon is isomer
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At the bottom of the perodic table...\n\nThey are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no. 85), francium (at. no. 87), and the transuranium elements (at. no. 93 and beyond in the periodic table). Some of these elements have since been shown to exist in minute amounts in nature, usually as short-lived members of natural radioactive decay series (see radioactivity).\n\nThe synthetic elements through at. no. 100 (fermium) are created by bombarding a heavy element, such as uranium or plutonium, with neutrons or alpha particles. The synthesis of the transfermium elements (elements with at. no. 101 or greater) is accomplished by the fusion of the nuclei of two lighter elements. Elements 101 through 106 were first produced by fusing the nuclei of slightly lighter elements, such as californium, with those of light elements, such as carbon. Elements 107 through 112 were first produced by fusing the nuclei of medium-weight elements, such as bismuth or lead, with those of other medium-weight elements, such as iron, nickel, or zinc. Element 114 was first produced by fusing the nuclei of plutonium and calcium and subsequently by fusing the nuclei of lead and krypton, as was element 116. Element 115 was produced by bombarding americium with calcium, and element 113 resulted from the radioactive decay of element 115. The claim by Lawrence Berkeley National Laboratory to have created element 118 has been retracted.)\n\nThe transfermium elements are produced in very small quantities (one atom at a time), and identification is therefore very difficult because of half-lives ranging from minutes to milliseconds and the need to identify the products by methods other than known chemical separations. This has led to controversy over reported discoveries and over the naming of the elements. It has been predicted that one isotope of element 114—containing 114 protons and 184 neutrons—would be very stable because its nucleus would have a full complement of protons and neutrons. Termed an “island of stability,” its half-life might be measured in years. However, none of the three isotopes of element 114 synthesized as yet have as many as 184 neutrons, and their half-lives are still in the millisecond range.
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Atoms of chemical elements may have many isotopes (different forms) with the same atomic numbers but different atomic weights / atomic mass numbers. If a nuclide is radioactive, it is sometimes referred to as a radionuclide or (when the atom in question is understood) a radioisotope.\n\nA radionuclide is an atom with an unstable nucleus. The radionuclide undergoes radioactive decay by emitting a gamma ray(s) and/or subatomic particles. Radionuclides may occur naturally, but can also be artificially produced.\n\nRadionuclides are often referred to by chemists and biologists as radioactive isotopes or radioisotopes, and play an important part in the technologies that provide us with food, water and good health. However, they can also constitute real or perceived dangers.
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Hydrogen came about through a process called Big Bang nucleosynthesis.  In the first three minutes of the universe's existence, hydrogen, helium, and trace amounts of lithium and beryllium came into existence.  Heavier elements formed only through fusion inside stars, much later.
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.The neutrons and protons are arranged in a nucleus by stong nuclear forces that are revealed in fission reactions..
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No; very few isotopes have been given individual names (there are far too many of them). The only ones I can think of are deuterium (hydrogen-2) and tritium (hydrogen-3).
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i wont point you to a link :)\n\nNuclear Synthesis is the process which forms newer heavier elements (e.g. iron ) from lighter elements ( e.g. hydrogen ).\n\nit does NOT occur naturally on Earth and is known to occur within stars during the final stages in their lifetimes. \n\nelements differ from each other by the weight of their nucleus ( center )  with hydrogen being the simplest with a weight of 1 .\n\ncombining 4 hydrogens will make  helium and this process is what the sun uses to burn.  in turn,  helium can be "fused" to make other heavier elements such as oxygen and carbon for example. ( see the periodic table ).\n\nthe process of fusing atoms requires great temperatures and pressures that not are present on earth ( except in thermonuclear bombs ! ) .  \n\nit is thought that all the elements were once created in the center of the many stars !\n\nin essence, everything ( except for hydrogen ) is made of star stuff !\n\nhope i resolved your confusion.
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Toxic atoms are just elements that have properties that are bad for life.\n\nRadioactive atoms are unstable, which means they fall apart all by themselves into smaller pieces. Usually a radioactive atom will throw off one or more neutrons to become the next lower element or isotope on the periodic table.\n\nAn isotope is an element that has a different number of neutrons in it's nucleus. For example, most carbon atoms have 6 protons and 6 neutrons in the nucleus.  That is a total of 12 particles so it is called carbon 12. Carbon 14 has two extra neutrons, or 6 protons and 8 neutrons. Because the number of electrons is always the same as the number of protons, and because chemistry is all based on electron interactions, both types of carbon behave the same chemically.\n\nA subatomic particle is a particle smaller than one atom. Atoms were once thought to be the smallest possible particle of matter, but we now know that they are made up of collections of various numbers of smaller particles called protons, neutrons and electrons.\n\nA "normal" atom would probably be the most stable isotope. For example carbon 14 is radioactive and changes into carbon 12 if given enough time, so carbon 12 might be considered more "normal". But I think the term "normal" is not clear and has no real meaning in this case. Certainly many naturally occurring elements are toxic, or radioactive or both.
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Do you mean enrichment?\n\nIf so \n\nNE is the process of concentrating specific isotopes of a chemical element by removing other isotopes, for example separating natural uranium into enriched uranium and depleted uranium. This is the crucial process in the creation of a nuclear weapon.\n\nWhile in general chemical elements can be purified through chemical processes, isotopes of the same element have nearly identical chemical properties, which makes this type of separation impractical, except for separation of deuterium.