Chemical Bonding

The Chemical Bonding article that discusses the nature of chemical bonding. This article begins with a simple explanation that chemical bonding is the “force that holds the atoms of various elements together” and that there are millions of combinations possible.

keynotes:

• Chemistry is alive and instead of focusing on the origin, we must seek to understand the evolution of discovery. As such, there are contributors to our modern understanding.

• Notable for his contribution to understanding the arrangement of chemical bonds, Gilbert N. Lewis created the “Lewis dot diagrams” to show electrons in the valence shell of atoms. His theory asserts that a bond is created when pairs of electrons on the valence shell are shared between atoms.

• In early to mid-20th century, Linus Pauling paired his understanding of the “chemical nature of the electron interactions” with the “physics of quantum mechanics” to evolve the understanding of chemical bonds.

• Arguably, Pauling’s greatest contribution was to identify that ionic bonds and covalent bonds sit opposite ends of a bonding spectrum and most chemical bonds can be classified somewhere along the spectrum. Further, he established a sliding scale bond type determined by the electronegativity of the atoms participating in the bond.

• Molecular bonds are formed when outer electrons are attracted to a positive nuclear charge. There are both attractive and repulsive forces as the atoms approach one another and seek a distance where these forces are reduced to a minimum, representing the most stable position.

focus: covalent and ionic bonds

• covalent bonds share electrons of the valence or outer shell

• sometimes, multiple pairs of electrons on the valence shell are shared so we have single bonds (single pair), double covalent (2 pairs shared // 4 electrons), and so on… the greater the sharing, the shorter and stronger the bond :)

• ionic bonds occur when electrons in the valence shell is shared so unequally between atoms that an electron hands out closer to the nuclei of its neighbor than its own, described as:

  • losing an electron > become net positive & called “cations”

  • gaining an electron >become net negative & called “anion”

  • ionic bonds exist between elements with a large difference in electronegativity

summary:

• bonds exist on a spectrum from pure ionic to pure covalent

• more types of bonds exist, e.g. metallic bonds, are other bonds are still being discovered, e.g. vibrational bonds