Nuclear reactions occur when the number of protons and neutrons in an atom's nucleus changes, much as chemical reactions cause compounds to transform into other compounds by exchanging electrons. Some nuclear processes can actually expel protons from the nucleus or convert them to neutrons. These processes are called radioactive decay because they result in a loss of mass and thus decay of the atomic nucleus. Other nuclear processes include fusion (the formation of a heavier element) and fission (the splitting of a heavy nucleus into two smaller nuclei). Neutrons are important in the study of nuclear physics because they can participate in these same nuclear reactions that change the number of protons and neutrons in an atom's nucleus. Thus, both alpha particles and neutrons are used in experiments to probe the structure of atoms and molecules.
When an atom loses one or more protons it becomes a neutron star. This is because there is no longer enough positive charge left over in the nucleus to keep the electron cloud around it. The atom has now decayed into something else, but since we don't know what else could contain a net positive charge we call this state "neutron-rich".
At the beginning of time, before any stars formed, there were only hydrogen atoms. As these atoms burned away their elements were left behind to form new generations of stars and planets.
Nuclear Alteration The nuclei are preserved throughout chemical change and merely change how they are bound together (the electrons). Nuclei can disintegrate to generate smaller components. Nuclei can combine to form heavier atoms. Neutrons can be converted into protons, and protons may be converted into neutrons. This process is called nuclear fission. Nuclear fusion is the reverse process - two nuclei merging to form one larger one. An example of nuclear fusion is when two protons collide and fuse to form a neutron plus a hydrogen atom. Another example is when two electrons orbit around an atomic nucleus non-productively (in other words, not forming negative energy states) and thus remain attached to it, resulting in its stabilization. This is known as electron binding by radiation.
Alteration means "to make different or new," so this phrase means "something that makes itself different or new." In science we use experiments to see what happens to elements when they are changed by heating or burning. We call the results of these experiments alterations.
Alterations of the nucleus occur in radioactive substances. Energy is released when nuclei decay, splitting themselves apart or being split by external forces. Radioactive materials become more abundant over time because the nucleus of each atom is changing as it decays.
Atoms' identities can be altered through nuclear processes that alter the amount of protons in their nucleus. Nuclear processes that modify the number of neutrons in an atom do not transform it into a new element. Isotopes are atoms that have the same number of protons but differing numbers of neutrons. An isotope can be considered to be another name for a chemical element. The term isotope is commonly used when referring to the elements that make up humans or other organisms, while the term compound is usually reserved for inorganic substances that contain more than one element.
Isotopes can be distinguished by their different atomic weights. All atoms have the same number of electrons as well as the same mass. The only difference between two atoms is their mass number - the total number of protons plus neutrons. For example, carbon has six protons and six neutrons, so its mass number is 12. Oxygen has eight protons and eight neutrons, so its mass number is 36. By comparing the masses of various isotopes, scientists can learn a lot about what happens to atoms during nuclear reactions. For example, physicists know that nuclei of some elements (such as uranium) can absorb particles (called alpha particles) with no effect on its identity. These are called stable isotopes because they do not change type or element when absorbing alpha particles. Other elements, such as nitrogen, can absorb alpha particles and become radioactive elements that produce energy in the form of gamma rays during this process known as alpha decay.
This is referred to as a chain reaction, and it is the cause of an atomic explosion. When a uranium-235 atom absorbs a neutron and fissions into two new atoms, three new neutrons and some binding energy are released. As a result, a nuclear chain reaction occurs. See Nuclear Fission for further information.
An atom is made up of protons, neutrons, and electrons. The number of protons in the nucleus must be equal to or greater than the number of neutrons, otherwise the atom would be too heavy to remain stable. Thus, the nucleus of an atom is typically composed of neutrons with a few protons attached, which creates a positive charge within the nucleus. An electron cloud surrounds each atom, giving it its color, but also keeping any other particles outside the nucleus at a distance. A hydrogen atom, which is the lightest atom, has one proton in its nucleus and one electron in its cloud. A uranium atom, which is very unstable without a neutron coating, will absorb a neutron and become highly radioactive. If enough neutrons are absorbed, their effects will be counteracted by photons being emitted during beta decay, and the atom will eventually decay into an inert product (which may be another element or just carbon dioxide). A nuclear explosion releases a large amount of energy in a very short time. This energy is found in the form of heat, light, and radioactivity.