Understanding Bond Energies: X-Y Bond Energy Contribution

In summary, the bond energy (E A-B) between two bonded atoms, X and Y, is greatly influenced by the difference in their electronegativities (eX and eY). When X is small and Y is large, the bond energy will have a large ionic contribution due to the high ionic character of the bond. This is determined by the percentage difference in the electronegativities of the two atoms. Therefore, the size of the respective atoms plays a significant role in determining the bond energy and its ionic character.
  • #1
guiromero
18
0
Hello.

Could someone please help me with this question about bond energy from an MIT course:

"For two bonded atoms X and Y, a small X and large Y will result in a bond energy (E A-B) with a large __________ contribution."

Thanks a lot if someone can help.
 
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  • #2
I've already gotten the answer, it's "ionic".
 
  • #3
Why is it ionic?
 
  • #4
I got this answer from another forum and the person said that these types of bonds have a high ionic character, which is the percentage of difference between the electronegativity of two covalently bonded atoms.
 
  • #5
Why would you expect the electronegativity of the respective atoms to depend upon the size of those atoms?
 
  • #6
Sorry, I forgot to correct the statement. The correct is like that:

"For two bonded atoms X and Y, a small eX and large eY will result in a bond energy (E A-B) with a large __________ contribution."

Where e = electronegativity
 

FAQ: Understanding Bond Energies: X-Y Bond Energy Contribution

What is bond energy and why is it important in chemistry?

Bond energy is the measure of the amount of energy required to break one mole of a particular type of bond in a molecule in the gas phase. It is important because it provides insights into the stability of molecules and the energy changes involved in chemical reactions. Understanding bond energies helps chemists predict reaction outcomes, design new molecules, and understand reaction mechanisms.

How is the bond energy of an X-Y bond determined experimentally?

The bond energy of an X-Y bond is determined experimentally using techniques such as spectroscopy, calorimetry, or by analyzing the enthalpies of formation and dissociation of related compounds. For example, the bond dissociation energy can be measured by determining the amount of energy required to break the bond in a controlled environment, often using high-energy light or heat.

What factors influence the bond energy of an X-Y bond?

Several factors influence the bond energy of an X-Y bond, including the types of atoms involved, the bond length, the bond order (single, double, triple), and the molecular environment. Electronegativity differences between atoms, hybridization states, and resonance effects also play significant roles in determining bond energies.

Why do bond energies vary between different types of bonds?

Bond energies vary between different types of bonds due to differences in atomic sizes, electronegativity, bond lengths, and the number of shared electron pairs. For example, triple bonds are generally stronger and have higher bond energies than double bonds, which in turn are stronger than single bonds. Additionally, polar bonds between atoms with significant electronegativity differences tend to have higher bond energies compared to nonpolar bonds.

How can bond energy data be used to predict the feasibility of a chemical reaction?

Bond energy data can be used to predict the feasibility of a chemical reaction by calculating the overall change in energy during the reaction. By comparing the total bond energies of reactants and products, chemists can determine whether a reaction is exothermic (releases energy) or endothermic (absorbs energy). Reactions that release energy are generally more feasible and spontaneous. This information helps in designing reactions and understanding reaction kinetics.

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