Where are we going with this? This page will give the ability to use laboratory observations and data to compare and contrast ionic, covalent, network, metallic, polar, and non-polar substances with respect to constituent particles, strength of bonds, melting and boiling points, and conductivity; provide examples of each type.
Polar Covalent Bonding
When atoms bond but…
When atoms bond but…
Polar covalent bonding occurs when two atoms form a covalent bond but have different electronegativities, causing the shared electrons to be attracted more strongly toward one atom. Polar covalent bonding usually occurs between two different nonmetals that have a noticeable difference in electronegativity.
Story (sort of) time…
So, hydrogen (H) is bopping along with one valence electron, while oxygen (O) has six valence electrons and needs two more to fill its valence shell. Hydrogen and oxygen can form covalent bonds by sharing electrons. BUT oxygen is greedy!
Oxygen's higher electronegativity causes it to “hog” the shared electrons! The shared electrons spend more time closer to the oxygen atom, giving the oxygen end of the bond a partial negative charge. As a result, the hydrogen end of the bond has a partial positive charge because the shared electrons spend less time near the hydrogen atom.
This is polar covalent bonding…
When there is a noticeable electronegativity difference between two covalently bonded atoms, the electrons are still shared, but they are shared unequally.
The more electronegative atom develops a partial negative charge (δ−), while the less electronegative atom develops a partial positive charge (δ+). These are partial charges—not full ionic charges.
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