unstable

Examples of unstable in the following topics:

• Nuclear Fission

  • These nuclei are called unstable, and this instability can result in radiation and fission.
  • The combination of these two produces 236U, which is an unstable element that undergoes fission.
  • In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process.
  • If U-235 is bombarded with a neutron (light blue small circe), the resulting U-236 produced is unstable and undergoes fission.

• Hydrophilic and Hydrophobic Colloids

  • Since the colloid does not interact with the aqueous solvent, hydrophobic colloids are inherently unstable and generally do not form spontaneously.
  • An example of this is seen in the separation of the oil and vinegar components of vinaigrette, an unstable emulsion that will quickly separate unless shaken almost continuously.
  • In C, the unstable emulsion progressively separates.

• Nuclear Stability

  • However, if neutron count surpasses an ideal ratio, a nucleus becomes unstable and can undergo radioactive decay.
  • Only 90 isotopes in this region are believed to be perfectly stable, while 163 more are understood to be theoretically unstable but have never been observed to decay.

• Nucleophilicity of Phosphorus Compounds

  • Phosphite esters react in the same manner, but the resulting phosphonium salts (shaded box) are often unstable, and on heating yield dialkyl phosphonate esters by way of a second SN2 reaction (equation 2 below).

• Modes of Radioactive Decay

  • Radioactive decay occurs when an unstable atomic nucleus emits particles or light waves.
  • Radioactive decay occurs when an unstable atomic nucleus loses energy by emitting energy in the form of emitted particles or electromagnetic waves, called radiation.
  • Some isotopes of a given element are more unstable than others, causing a nuclear reaction which releases energy to achieve a more stable nuclear configuration.

• Reaction of Amines with Nitrous Acid

  • Because it is unstable, it is prepared immediately before use in the following manner:
  • Loss of nitrogen is slower than in aliphatic 1º-amines because the C-N bond is stronger, and aryl carbocations are comparatively unstable.

• Elimination

  • The intermediate in this mechanism is an unstable benzyne species, as displayed in the the second diagram above.

• Antiaromaticity

  • Planar bridged annulenes having 4n π-electrons have proven to be relatively unstable.

• Isotopes of Hydrogen

  • Other highly unstable nuclei (4H to 7H) have been synthesized in the laboratory, but do not occur in nature.
  • It is a highly unstable isotope of hydrogen.
  • 5H is another highly unstable heavy isotope of hydrogen.

• Sulfur Compounds

  • Other oxides are known—sulfur monoxide and disulfur mono- and dioxides—but they are unstable.
  • Sulfur dioxide and sulfites (SO32−) are related to the unstable sulfurous acid (H2SO3).
  • Peroxides convert sulfur into unstable compounds such as S8O, a sulfoxide.