User:Verazzano/sandbox

Chemical elements exist in different isotopes, each of which belongs to that element and exhibits its characteristic properties. The atomic nucleus is made up of nucleons, of which there are two types: protons and neutrons. The number of protons in an atom is sufficient to identify its atomic element, while both the number of protons and the number of neutrons identifies a particular isotope. Either the proton number and the neutron number

At least two separate pieces of information are needed in order to identify a particular isotope. First, one must either know the element of that isotope, or the atomic number (Z) that uniquely corresponds to that element. Second, either the neutron number (N) or the nucleon number (A) is needed in order to further specify the particular isotope of that element. As long as one knows the atomic number (Z), it makes no difference whether the second piece of information is the neutron number (N) or the nucleon number (A), since one may convert between the latter two figures, using the formula: A = Z + N.

By convention, an isotope is typically identified by the name of the element and the mass number. Thus, for example, it would be standard to indicate the isotopes of carbon as: carbon-12, carbon-13, and carbon-14. Yet, as explained above, this is just a convention, and an isotope may be uniquely identified as long as one knows the number of protons in that atom, and either the number of neutrons or the mass number.

In order to determine what isotope an atom belongs to, two pieces of information are required: its number of neutrons, and its number of protons. The protons indicate the element to which that isotope belongs, with the number of neutrons specifies the particular isotope of that element. By convention, isotopes are identified by naming both the element, and the total number of nucleons.

An isotope is a variant of a given chemical element. While an element is defined by the number of protons found in any atom of that element, an isotope is defined both by the number of protons (which identifies the element it belongs to) and also by the number of neutrons (which identifies the particular isotope of that element). Thus identifying an isotope requires more information than identifying an element.

By convention, isotopes are typically identified by giving the name of the element and the mass number (or total number of nucleons). Thus, for example, one could refer to carbon-12, carbon-13, and carbon-14. Informationally, this is equivalent to giving the number of protons and the number of neutrons, since the number of neutrons can be determined by subtracting the atomic number from the mass number.

Isotopes are variants of a particular chemical element. While all isotopes of a given element share the same number of protons, each isotope differs from the others in its number of neutrons. The term isotope is formed from the Greek roots isos (ἴσος "equal") and topos (τόπος "place"). Hence: "the same place," meaning that different isotopes of a single element occupy the same position on the periodic table. The number of protons within the atom's nucleus uniquely identifies an element, but a given element may in principle have any number of neutrons. The number of nucleons (protons and neutrons) in the nucleus, known as the mass number, is not the same for two isotopes of any element. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively. The atomic number of carbon is 6 (every carbon atom has 6 protons); therefore the neutron numbers in these isotopes are 6, 7 and 8 respectively.