bond energy

Question 1

what is the definition of bond energy?

Answer 1

bond energy is the average energy required to break 1 mole of covalent bond in the gas phase into constituent atoms under standard conditions

Question 2

what does bond energy indicate?

Answer 2

the strength of covalent bonds

Question 3

what constitutes a stronger covalent bond?

Answer 3

greater bond energy

Question 4

what are the 2 factors affecting average bond energies?

Answer 4

1. extent of atomic orbital overlap between 2 bonded atoms
2. bond order

Question 5

how does the extent of atomic orbital overlap between two bond atoms affect average bond energies?

Answer 5

• the greater the extent of atomic orbital overlap, the stronger the attraction between electrons in the overlap & the nuclei of the atoms
• resulting in a stronger bond, & hence greater bond energy

Question 6

how does the bond order affect average bond energies?

Answer 6

• the greater the bond order, the stronger the covalent bond
• hence, bond energy is greater

Question 7

explain why is the bond energy of the C=C < 2(bond energy of C-C).

Answer 7

• as C-C is a σ bond, while C=C consists of 1 σ & 1 𝜋 bond
• as 𝜋 bond is weaker than σ bond due to a lesser extent of orbital overlap of atomic orbitals