Three main components make an atom-protons, neutrons in the nucleus, and electrons in the outer nuclear region.
In nuclear reactions, the nucleus reacts, whereas, in organic chemical reactions and other bonding reactions, the crucial involvement is of the electrons. Also, not all of an atom’s electrons are reactive, only some are, and this decision is made based on its placement around the nucleus.
The electrons are arranged in various shells around an atom; the inner shells are closest to the nucleus. These shells containing the electrons are complete, stable, and inert. The outermost shell, called the valence shell, is incomplete, unstable, and the one that takes part in reactions. The stability that the valence shell is looking for is called octet stability, that is, eight electrons in the outermost shell.
Reactions offer a means for the outermost shell to acquire new electrons or give away electrons that do not contribute to an atom’s stability. The stability that the valence shell or the outermost shell is looking for is called octet stability. That is, if there are eight electrons in the outermost shell, then a stable state of an atom has been reached.
- For more information on how the electrons are arranged around the nucleus, the valence shell of an atom and its identification, and octet stability, subscribe to CurlyArrows Organic Chemistry Course.