Search results
Results from the WOW.Com Content Network
118 chemical elements are known to exist. All elements to element 94 are found in nature, and the remainder of the discovered elements are artificially produced, with isotopes all known to be highly radioactive with relatively short half-lives (see below). The elements in this list are ordered according to the lifetime of their most stable ...
A contact explosive is a chemical substance that explodes violently when it is exposed to a relatively small amount of energy (e.g. friction, pressure, sound, light). Though different contact explosives have varying amounts of energy sensitivity , they are all much more sensitive relative to other kinds of explosives.
In chemistry, the term chemically inert is used to describe a substance that is not chemically reactive.From a thermodynamic perspective, a substance is inert, or nonlabile, if it is thermodynamically unstable (positive standard Gibbs free energy of formation) yet decomposes at a slow, or negligible rate.
All the first 66 elements, except 43, 61, 62, and 63. If spontaneous fission is possible for the nuclides with mass numbers ≥ 93, then all such nuclides are unstable, so that only the first 40 elements would be stable. If protons decay, then there are no stable nuclides. Energetically unstable to one or more known decay modes, but no decay ...
All others are under a minute, most under a second. The least stable is 15 Ne with a half-life of 770(300) ys (7.7(3.0) × 10 −22 s). See isotopes of carbon for notes about the measurement. Light radioactive neon isotopes usually decay to fluorine or oxygen, while heavier ones decay to sodium.
Most of the isotopes with atomic mass numbers below 14 decay to isotopes of carbon, while most of the isotopes with masses above 15 decay to isotopes of oxygen. The shortest-lived known isotope is nitrogen-10, with a half-life of 143(36) yoctoseconds , though the half-life of nitrogen-9 has not been measured exactly.
In chemistry, chemical stability is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. [1]Chemical stability may also refer to the shelf-life of a particular chemical compound; that is the duration of time before it begins to degrade in response to environmental factors.
The study of molecules by molecular physics and theoretical chemistry is largely based on quantum mechanics and is essential for the understanding of the chemical bond. The simplest of molecules is the hydrogen molecule-ion , H 2 + , and the simplest of all the chemical bonds is the one-electron bond .