Dipoles vs Ions

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Elena Chen 2E
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Dipoles vs Ions

Postby Elena Chen 2E » Sat Nov 14, 2020 10:50 pm

Hi, can someone please explain what exactly is the difference between an ionic bond and a dipole moment, if they both have differences in charge/electronegativity between the atoms involved? What makes a molecule an ion instead of a dipole?

Stuti Pradhan 2J
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Re: Dipoles vs Ions

Postby Stuti Pradhan 2J » Sat Nov 14, 2020 11:09 pm

An easy way to tell the difference is that ions tend to lose of gain electrons resulting in charges, such as Na+, or Cl-, whereas a dipole indicates an unequal sharing of electrons due to differences in electronegativity, resulting in some partial charges. If the difference in electronegativity is greater than 2, then it is likely ionic bond, but if the difference is less than 1.5, then the bond is most likely covalent.

I believe ions or ionic compounds have more distinct charges, meaning that all the electrons essentially belong to one of the ions in the compound, whereas in a dipole, they are more attracted to one of the atoms but are still shared. However, since ionic bonds can have some covalent character and covalent bonds can have some ionic character, I do not think this is a rule because a stronger dipole would pull the electrons further apart, resulting in more ionic character of an covalent bond.

Hope this helps!
Last edited by Stuti Pradhan 2J on Sat Nov 14, 2020 11:20 pm, edited 2 times in total.

Nathan Lao 2I
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Re: Dipoles vs Ions

Postby Nathan Lao 2I » Sat Nov 14, 2020 11:14 pm

An ionic bond essentially involves the transfer of an electron, usually from a metal to nonmetal, to achieve a lower energy. A dipole moment is a separation of charge due to differences in electronegativity. There is a momentary unequal distribution of electrons that leads to a dipole moment.

Emerald Wong 1B
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Re: Dipoles vs Ions

Postby Emerald Wong 1B » Sat Nov 14, 2020 11:19 pm

In an ionic bond, electrons are transferred from one atom to another, while dipole moments occur due to a unequal distribution of electrons. Ionic bonds also arise due to the molecules themselves having charges, while dipole moments come from differences in electronegativity.

IanWheeler3F
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Re: Dipoles vs Ions

Postby IanWheeler3F » Sun Nov 15, 2020 8:40 pm

Like everyone is saying, the difference between the two is how electrons are shared, ionic completely moves the electron but dipoles unequally share them. But the way I like to think about unequal electron sharing in dipoles is the resonance structure. The bond in HF is a single bond where hydrogen shares an electron with fluorine so eight electrons total, but really it is a resonance between hydrogen having two electrons and fluorine having six in one state, and hydrogen having no electrons and fluorine having eight electrons. However between these two states one is more likely to happen, that being the second structure where fluorine has eight electrons and hydrogen has none which makes fluorine negatively charged and hydrogen positively charged. But that only happens for a second since the first structure still happens where hydrogen is negative and fluorine is positive. This unequal sharing of the electrons in the resonance causes the dipole (opposite charges) to form.

Thomas Gimeno
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Re: Dipoles vs Ions

Postby Thomas Gimeno » Sun Nov 15, 2020 9:51 pm

Well so ionic and covalent bonds are the opposite ends of the spectrum of electronegativity difference with ionic having a high difference and covalent having a small difference. A dipole moment occurs when a bond has a significant difference in electronegativity but the difference is not high enough to be considered an ionic bond. This resaults in the uneven sharing of electrons even though the bond is still considered covalent.


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