Bonding L11 Flashcards
1
Q
Continuous spectrum
A
Every wavelength of light is represented in the continuous spectrum
2
Q
Atomic emission spectrum
A
- Different energies=different colors
- Every element produces different emissions/colors
3
Q
Why do we have different colors of light?
A
- As wavelength/frequency changes, color changes
- But light behaves like a wave and it behaves like a particle
- As wavelength/frequency changes, the energy per photon changes
4
Q
Hybrid orbital theory
A
- Atomic orbitals on the same atom combine in order to form hybrids
- Atomic orbitals on different atoms overlap in order to form covalent bonds
- Each atom in the compound retains its associated orbitals and electrons
- This theory correlates with observed bond angles in molecules
5
Q
Molecular Orbital Theory
A
- Views molecules as a whole instead of a collection of individual atoms
- MOs are similar to atomic orbitals
- They both have specific energy levels
- Atomic orbitals combine to form MOs
- When two atomic orbitals combine, two MOs are formed
- Orbitals are always conserved
6
Q
Bonding orbital
A
- A MO that is lower in energy than any atomic orbitals from which it was derived
- Electrons that occupy these orbitals cause stability
7
Q
Anti-bonding orbital
A
- A MO that is higher in energy that any atomic orbitals from which it was derived
- Electrons that occupy these orbital cause instability
8
Q
Non-bonding orbital
A
- A MO that is at the same energy level as the one atomic orbital it was derived from
- Electrons that occupy these orbitals do not cause stability or instability
- Orbitals that contain lone pairs
9
Q
Spectroscopy
A
- A method of analysis which is based upon the absorbance of electromagnetic radiation by matter
- Used to acquire data pertaining to the structure of a molecule or the concentration of a species
10
Q
UV/V spectroscopy
A
- Examines transitions in electronic energy levels
- used to probe the electronic structure of certain compounds
- used to determine concentrations of solutions that contain certain compounds
11
Q
Infrared IR spectroscopy
A
- Examines transitions in molecular vibrations
- Is used to detect the presence of different types of bonds and to identify molecules
12
Q
UV/V graphs
A
- An absorption spectrometer is used to measure the absorbance of a sample at wavelengths between 200 and 800 nm
- The peaks represent wavelengths that correspond to the energy associated with possible electronic transitions within the molecule
13
Q
What transitions can take place in UV/V between 200nm and 800nm
A
- pi (bonding) to pi anti-bonding
- pi non-bonding to pi anti-bonding
- pi non-bondign to sigma anti-bonding
14
Q
beers law
A
A=abc
- A=absorbance
- a=molar absorptivity (M-1cm-1)
- b=path length of sample(cm)
- c=concentration (M)
15
Q
IR spectroscopy
A
- all covalent bonds in molecules are vibrating
- bond length is the average distance between nuclei
- Covalent bonds have a vibrational frequency that is in the IR region of the electromagnetic spectrum
- IR radiation of exactly the same frequency will be absorbed by the molecule
- vibration frequencies depend on the mass of the atoms and the strength of the bonds
- frequency is related to wavelength
