Bond Length, Strength, and Order Flashcards
Effect of atomic size, hybridization, and resonance
The distance between the nuclei bond
Bond Length
How is Bond Length determined experimentally?
X-Ray diffraction or Analysis of Molecular Spectra
Who?
Elucidate the double helix structure of DNA
Through photo 51
Rosalind Franklin
What is the unit of Bond Length?
Angstrom
Orbital
What is required to form a covalent bond?
Overlapping orbital
High or low?
At what level of energy does a molecule form a covalent bond in an optimal distance?
Low potential energy
At low potential energy, the molecule become stable
Repulsion occurs at high energy
Quantified by bond energy or bond dissociation energy
Bond Strength
It is the energy required to break a chemical bond
Bond Strength
Bond Energy vs Bond Strength
The higher the bond energy,
the higher the bond strength
Effect of Atomic Size
The greater the size of overlap, the ____ the efficiency of the bond strength
higher
Which one has a stronger Bond Strength?
H - F or H - I
H - F
The atomic size of Flourine is smaller than Iodine
Distance between the nuclei of H and F is shorter
Which one has a longer Bond Length?
H - F or H - I
H - I
The atomic size of Iodine is larger than Iodine
Distance between the nuclei of H and I is longer
Bond Length vs Bond Strength
The longer the bond length,
the smaller the bond strength.
This relationship is helpful on diatomic molecules
Which one has a stronger Bond Strength?
C-C or H - H
H - H
The atomic size of H is smaller than C
Overlapping of valence orbital is more efficient
Which one has a longer Bond Length?
C - C or H - H
C - C
The atomic size of C is bigger than H
Effect of hybridization
The higher the s-character
the shorter the BL; the higher the BS
BL = Bond Length, BS = Bond Strength
Effect of hybridization
The higher the p-character
the longer the BL; the lower the BS
BL = Bond Length, BS = Bond Strength
The number of chemical bonds between a pair of atoms
Bond Order
What is the formula for getting Bond Order (BO)?
BO = (no. of bonds orginating from ref. atom)/(no. of outer atoms)
What is the value of Bond Order of a Resonance?
A fraction number
Bond Order vs Bond Strength
The higher the Bond Order,
The higher the Bond Strength
What makes Resonance higher in Bond Order than a non-Resonance molecule?
Resonance have partial double bond character
Note: Resonace is a stabilizer.
The higher the Bond Order, the higher the Bond Strength
Higher or lower?
Resonance has a ____ bond strength
higher
Bond Order vs Bond Length
The higher the Bond Order,
the shorter the Bond Length
Another proponent/s for X-ray Diffraction
Watson and Crick
