Flashcards
Knowledge Questions Physical Chemistry
Cards in this deck (20)
- 1Describe the subatomic structure of an atom.An atom consists of a nucleus, with protons and neutrons that are surrounded by electrons.
- 2What are the forces that hold an atom together?Nuclear force holding the protons and neutrons together in the centre of the atom, electrostatic force between the protons and electrons.
- 3What are the letters used to designate mass number and atomic number?A - mass number
Z - atomic (proton) number - 4Why do isotopes exist?Because atoms of elements have the same number of protons but can have different numbers of neutrons.
- 5Why do isotopes of an element have the same chemical properties?Because they have the same electron configuration.
- 6What are the stages in a Time of Flight Mass spectrometer?Ionisation, Acceleration to constant kinetic energy, ion drift, ion detection, data analysis.
- 7What are the two ionisation processes in a TOF spectrometer and when are they used?Electron impact for elements and substances with low relative molecular mass.
Electron spray for larger organic molecules. - 8What is the definition of relative atomic mass?Average mass of 1 atom/ 1/12th the mass of 1 atom of 12C.
- 9Which three equations do you need to use to work out the mass of an atom of an isotope using data from a TOF spectrometer?Velocity = distance/time
Kinetic energy = ½ mv2
Mass of 1 ion = mass of 1 mole/Avogadro’s constant - 10What are the axes on a mass spectrum?Y axis - relative abundance (%)
X axis - mass/charge (m/z) - 11Which peak on a mass spectrum of a molecule tells you the relative molecular mass?The molecular ion peak; the peak with the largest m/z.
- 12Describe the electron configurations in terms of shells and sub-shells (orbitals) s, p, and d of: 23 11 Na+ 48 48 Ti1s2 2s2 2p6
1s2 2s2 2p6 3s2 3p6 4s2 3d2 - 13What is ionisation energy (IE)?The energy required to remove a mole of electrons from a mole of atoms in the gaseous state measured in KJ mol-1.
- 14Define first ionisation energyThe first ionisation energy is the enthalpy change when one mole of gaseous atoms forms one mole of gaseous ions with a single positive charge.
- 15Write equations for the first, second and third ionisation energies of an at atom using M as the symbol for the element?M(g) → M+(g) + e-
M+(g) → M2+(g) + e-
M2+(g) → M3+(g) + e- - 16What factors affect IE?Attraction of the nucleus
Distance of the electron from the nucleus
Shielding of the attraction of the nucleus. - 17Describe the trend in first IE across Period 3.Increases with a small drop from Magnesium to Aluminium and from Phosphorus to Sulfur.
- 18Explain the slight drop in IE between Mg and AlAl is starting to fill a 3p sub shell, whereas Mg has its outer electrons in the 3s
sub shell. The electrons in the 3p subshell are slightly easier to remove because
the 3p electrons are higher in energy and are also slightly shielded by the 3s
electrons - 19Describe the trend in IE down a group.Decreases.
- 20When will there be a big jump in IE when progressively removing electrons from an atom?When that electron is being removed from a shell that is closer to the nucleus.
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- Flashcards on Knowledge Questions Physical Chemistry, created by Jasmine Bayliss-Dagg on 10/01/2018.
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- Jasmine Bayliss-Dagg
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