Understanding Covalent Bonds: Why Do They Hold Molecules Together?

In summary, covalent bonds are formed when the attractive force between two positive nuclei and a shared negative electron exceeds the repulsive force between the two nuclei. This binding energy is weaker than the strong force within the nucleus. Covalent theory is widely accepted by quantum physicists and the distance between nuclei and the shared electron is on average the same. A good explanation of covalent bonding can be found in the article by Kutzelnigg.
  • #1
RichyOwen
6
0
I took chemistry a couple years ago but never got a satisfactory answer as to why covalent bonds hold molecules together. I understand that they share their outermost electrons, but why would that keep them together? Do the electrons pull against each other or something?
 
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  • #2
Welcome to PhysicsForums, RichyOwen!

A simple way of considering it: if two positive nuclei are attracted to the same negative electron, and that attractive force exceeds the repulsion of the two positive nuclei, then net attraction means the nuclei form a covalent bond.

That binding energy is not very strong compared to the binding of positively charged protons and neutrons due to the strong force within the nucleus, of course.
 
  • #3
Thanks so much! I was quite puzzled. Do you know if covalent theory is accepted by most quantum physicists?
 
  • #4
Also, will the two nuclei then be the same distance (on average) from the shared electron?
 
  • #5
RichyOwen said:
Thanks so much! I was quite puzzled. Do you know if covalent theory is accepted by most quantum physicists?
Yes, it is. The question would have been maybe more apt for the Atomic, solid state, comp phys forum.
One of the best explanations of covalent bonding in my opinion is given in this article by Kutzelnigg:
http://onlinelibrary.wiley.com/doi/10.1002/anie.197305461/abstract
 
  • #6
Sorry I'm new to this forum stuff. Thank you!
 

Related to Understanding Covalent Bonds: Why Do They Hold Molecules Together?

1. What is a covalent bond?

A covalent bond is a type of chemical bond formed between two atoms when they share one or more pairs of electrons. This bond is formed when the outermost electrons of the atoms overlap with each other, creating a strong attraction between the two atoms.

2. Why do covalent bonds hold molecules together?

Covalent bonds hold molecules together because the shared electrons create a strong electrostatic attraction between the atoms, keeping them close together. This sharing of electrons allows the atoms to achieve a more stable electron configuration.

3. How do covalent bonds differ from other types of chemical bonds?

Covalent bonds differ from other types of chemical bonds, such as ionic or metallic bonds, because they involve the sharing of electrons between atoms rather than the transfer or pooling of electrons. This sharing results in a more equal distribution of electrons and a stronger bond between the atoms.

4. What factors affect the strength of a covalent bond?

The strength of a covalent bond is affected by several factors, including the type of atoms involved, the number of shared electrons, and the distance between the atoms. Generally, the closer the atoms are and the more electrons they share, the stronger the covalent bond will be.

5. How do covalent bonds contribute to the properties of molecules?

Covalent bonds play a crucial role in determining the physical and chemical properties of molecules. The strength and arrangement of covalent bonds affect the molecule's melting point, boiling point, polarity, and reactivity. The types of atoms involved in the covalent bond also determine the types of chemical reactions the molecule can undergo.

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