uestion 10: Mark each statement as True or False (10 points): Statement True Fal
ID: 1045475 • Letter: U
Question
uestion 10: Mark each statement as True or False (10 points): Statement True False Auger electron spectroscopy can provide information about chemical bonding. Adiabatic ionization energy (IE) of a molecule is generally Fragment ion appearance energies for most molecules are always 20% higher than their IE higher than its vertical IE values LD and Cl both yield M* ions. ICP MS provides functional group and structural information for most molecules o Beam chopping and continuum-source correction are both among background correctiono techniques in atomic absorption and atomic emission spectroscopy MALDI, ESI, Cl, and El are all among "soft lonization" techniques Most El mass spectra are obtained at 70 ev because molecules do not ionize below 50 ev. Reflectrons are used to see the reflection of ions in the ionization source. XPS provides information about intact molecule on any surface.Explanation / Answer
1. Auger Electron spectoscopy can provide information about chemical bonding -TRUE
reason- in Auger electron spectroscopy , auger electons energy is directly related to the binding energies of electron in surface atoms. Any chemical bonding to a metal surface , such as by an adsorbed molecule , will necessarily change the energies of electrons in outer orbitals of the surface atoms i.e. Auger spectroscopy can provide information about the type of bonding which occurs.
2. Statement given is False, Adiabatic IE is the minimum amount of energy required to remove an electron from a neutral molecule. Vertical ionisation involves vibrational excitation of an ionised state and hence more energy is requred .
3.Statement given isTRUE Ionisation energy for most molecules are in the range 7-15 eV. Fragment ions will be having excess K.E as a result of the energy received from ionisation source.
4. Statement given is False, as Laser desorption produces (M+H)+ ions
5. Statement given is False, ICP MS is usually employed for elemental analysis.
6.Statement given is True, both are used in Atomic Absorption Spectroscopy and Atomic Emission Spectroscopy
7.Statement given is False, as MALDI and ESI are soft ionisation techniques where as CI and EI are hard ionisation techniques.
8.Statement given is False, most of the molecules has ionisation potential ranging between 8-15eV. To create ions with high efficiency and to produce reproducible spectral features, including fragmentation patterns a standard 70eV electron beam is used.
9.Statement given is True . reflectron is an electrostatic device used in time-of -flight mass spectrometer.
10.Statement given is False, XPS provides information about core electrons and not about the surface electrons.
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