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An even number of protons or neutrons is more stable (higher binding energy) because of pairing effects, so even–even nuclides are much more stable than odd–odd. One effect is that there are few stable odd–odd nuclides: in fact only five are stable, with another four having half-lives longer than a billion years.
In chemistry, chemical stability is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. [ 1 ] Thermodynamic stability occurs when a system is in its lowest energy state , or in chemical equilibrium with its environment.
It is widely believed that an island of stability exists along the beta-stability line for isotopes of elements around copernicium that are stabilized by shell closures in the region; such isotopes would decay primarily through alpha decay or spontaneous fission. [13] Beyond the island of stability, various models that correctly predict many ...
For this reason, the valley of stability does not follow the line Z = N for A larger than 40 (Z = 20 is the element calcium). [3] Neutron number increases along the line of beta stability at a faster rate than atomic number. The line of beta stability follows a particular curve of neutron–proton ratio, corresponding to the most stable ...
HSAB is widely used in chemistry for explaining the stability of compounds, reaction mechanisms and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to chemical species . 'Hard' applies to species which are small, have high charge states (the charge criterion applies mainly to acids, to a lesser extent to bases), and are ...
This stability tends to prevent beta decay (in two steps) of many even–even nuclides into another even–even nuclide of the same mass number but lower energy (and of course with two more protons and two fewer neutrons), because decay proceeding one step at a time would have to pass through an odd–odd nuclide of higher energy.
The relationship between diversity and stability has been widely studied. [4] [21] Diversity can enhance the stability of ecosystem functions at various ecological scales. [22] For example, genetic diversity can enhance resistance to environmental perturbations. [23] At the community level, the structure of food webs can affect stability.
In mathematics, structural stability is a fundamental property of a dynamical system which means that the qualitative behavior of the trajectories is unaffected by small perturbations (to be exact C 1-small perturbations). Examples of such qualitative properties are numbers of fixed points and periodic orbits (but not their periods