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Ionic bonds join two ions, covalent bonds join two nonmetal atoms. If the electronegativity difference is >2 then it is considered an ionic bond, if electronegativity difference is <1.5 then it is considered a covalent bond.
Last edited by Deborah Cheng 1F on Mon Nov 13, 2017 8:14 pm, edited 1 time in total.
Deborah Cheng 3K wrote:Ionic bonds join two nonmetal atoms, covalent bonds join two ions. If the electronegativity difference is >2 then it is considered an ionic bond, if electronegativity difference is <1.5 then it is considered a covalent bond.
This first part of this answer is a bit mixed up: ionic bonds join ions (think of it like one atom steals the e- of the other) whereas covalent bonds join nonmetals through the sharing of e-.
The best way to tell is that the electro negativity is <1.5 for covalent bonds and is >2 for ionic bonds. It is also important to realize that some ionic bonds have covalent bond characteristics, and some covalent bonds have ionic bond characteristics. This depends on the extent of attraction of an electron to the atom.
I've always held the notion that ionic bonds were stronger than covalent bonds (it takes more [heat] energy to melt salt than it does to melt ice), but the Sunday review session (3 - 4 pm) the TA mentioned that ionic bonds are weaker in water. My question is as follows: given a question "Order the bonds in order of strongest to weakest: ionic, covalent, _____. _____" would ionic be stronger or weaker than covalent?
Ionic bonds have a very high difference in electronegativities. They tend to occur between a metal and a nonmetal as metals (metals have low electronegativities and nonmetals have high electronegativities). Covalent bonds, by comparison, have a low difference in electronegativity. They tend to occur between 2 nonmetals. Ionic bonds are very soluble in water because of the cation and anion inside. They also are brittle with high melting points. They have a much higher bond strength than covalent bonds. Covalent bonds aren't soluble in water and tend to have low melting points.
Ionic bonds have one atom "donating" an electron to another atom. This creates an anion and a cation that are held together by electronegativity, by how their differing charges attract, a relatively weak bond. This also causes them to usually form crystalline structures and be soluble in water, creating a conducting solution.
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