| Date | May 2018 | Marks available | 2 | Reference code | 18M.2.hl.TZ1.2 |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Sketch | Question number | 2 | Adapted from | N/A |
Question
Calcium carbide, CaC2, is an ionic solid.
Describe the nature of ionic bonding.
Describe how the relative atomic mass of a sample of calcium could be determined from its mass spectrum.
When calcium compounds are introduced into a gas flame a red colour is seen; sodium compounds give a yellow flame. Outline the source of the colours and why they are different.
Suggest two reasons why solid calcium has a greater density than solid potassium.
Outline why solid calcium is a good conductor of electricity.
Sketch a graph of the first six ionization energies of calcium.
Calcium carbide reacts with water to form ethyne and calcium hydroxide.
CaC2(s) + H2O(l) → C2H2(g) + Ca(OH)2(aq)
Estimate the pH of the resultant solution.
Describe how sigma (σ) and pi () bonds are formed.
Deduce the number of σ and bonds in a molecule of ethyne.
Markscheme
electrostatic attraction AND oppositely charged ions
[1 mark]
multiply relative intensity by «m/z» value of isotope
OR
find the frequency of each isotope
sum of the values of products/multiplication «from each isotope»
OR
find/calculate the weighted average
Award [1 max] for stating “m/z values of isotopes AND relative abundance/intensity” but not stating these need to be multiplied.
[2 marks]
«promoted» electrons fall back to lower energy level
energy difference between levels is different
Accept “Na and Ca have different nuclear charge” for M2.
[2 marks]
Any two of:
stronger metallic bonding
smaller ionic/atomic radius
two electrons per atom are delocalized
OR
greater ionic charge
greater atomic mass
Do not accept just “heavier” or “more massive” without reference to atomic mass.
[2 marks]
delocalized/mobile electrons «free to move»
[1 mark]
general increase
only one discontinuity between “IE2” and “IE3”
[2 marks]
pH > 7
Accept any specific pH value or range of values above 7 and below 14.
[1 mark]
sigma (σ):
overlap «of atomic orbitals» along the axial/internuclear axis
OR
head-on/end-to-end overlap «of atomic orbitals»
pi ():
overlap «of p-orbitals» above and below the internuclear axis
OR
sideways overlap «of p-orbitals»
Award marks for suitable diagrams.
[2 marks]
sigma (σ): 3
AND
pi (): 2
[1 mark]
Examiners report
Syllabus sections
-
17M.1.hl.TZ1.5:
Which statement explains one of the decreases in first ionization energy (I.E.) across period 3?
A. The nuclear charge of element Al is greater than element Mg.
B. The electron-electron repulsion is greater, for the electron with the opposite spin, in element S than in element P.
C. A new sub-level is being filled at element S.
D. The p orbital being filled in element Al is at a lower energy than the s orbital in element Mg.
-
22M.1.hl.TZ1.5:
The graph shows the first six ionization energies of an element.
[Ionization energies of the elements (data page) Available at: https://en.wikipedia.org/wiki/Ionization_energies_of_the_
elements_(data_page) Text is available under the Creative Commons Attribution-ShareAlike License 3.0 (CC BY-SA
3.0) https://creativecommons.org/licenses/by-sa/3.0/deed.en.]
In which group is the element?A. 13
B. 14
C. 15
D. 16
- 18M.1.hl.TZ2.5: The graph shows the first ionization energies of some consecutive elements. Which...
- 18M.1.hl.TZ1.5: Which transition on the diagram corresponds to the ionization of hydrogen in the ground state?
-
17M.2.hl.TZ1.2d.iv:
Explain why an aluminium-titanium alloy is harder than pure aluminium.
- 16N.1.hl.TZ0.6: A period 3 element, M, forms an oxide of the type M2O. Which represents the first four...
- 18N.1.hl.TZ0.5: The values for the first three successive ionization energies for two elements X and Z are...
- 18N.2.hl.TZ0.4c: Sketch a graph to show the relative values of the successive ionization energies of boron.
- 19M.1.hl.TZ1.5: Which element is represented by the first eight successive ionization energies on the...
-
19M.1.hl.TZ2.5:
Which of the following transitions in the hydrogen atom emits the least energy?
A. n = 2 to n = 1
B. n = 3 to n = 1
C. n = 4 to n = 2
D. n = 4 to n = 3
-
17N.1.hl.TZ0.6:
The graph represents the first ten ionisation energies (IE) of an element.
What is the element?
A. O
B. S
C. Ne
D. Cl
-
18M.2.hl.TZ2.3a.iii:
Hydrogen spectral data give the frequency of 3.28 × 1015 s−1 for its convergence limit.
Calculate the ionization energy, in J, for a single atom of hydrogen using sections 1 and 2 of the data booklet.
-
16N.2.hl.TZ0.4d:
(i) Explain the convergence of lines in a hydrogen emission spectrum.
(ii) State what can be determined from the frequency of the convergence limit.
-
17M.2.hl.TZ2.4c:
The first six ionization energies, in kJ mol–1, of an element are given below.
Explain the large increase in ionization energy from IE3 to IE4.
-
19M.2.hl.TZ1.3a:
Plot the relative values of the first four ionization energies of sodium.
-
17M.2.hl.TZ1.2d.iii:
Sketch a graph of the first six successive ionization energies of vanadium on the axes provided.
-
19N.2.hl.TZ0.1e(ii):
Determine, showing your working, the wavelength, in m, of ultraviolet light absorbed by a single molecule in one of these steps. Use sections 1, 2 and 11 of the data booklet.
- 19N.1.hl.TZ0.5: Which shows the first ionization energies of successive elements across period 2, from left...
- 21M.1.hl.TZ1.6: The diagram shows the first ionisation energies of consecutive elements in the same period of...
- 21M.2.hl.TZ1.1c: Sketch the first eight successive ionisation energies of sulfur.
- 21M.1.hl.TZ2.5: The first eight successive ionization energies for an element are shown. In which group is...
-
19M.2.hl.TZ2.3c:
Explain why the first ionization energy of nitrogen is greater than both carbon and oxygen.
Nitrogen and carbon:
Nitrogen and oxygen:
- 22M.2.hl.TZ2.5a(ii): Explain why there is a large increase from the 8th to the 9th ionization energy of iron.
- 20N.1.hl.TZ0.5: Which element is in group 13?
-
20N.2.hl.TZ0.6a:
The electron configuration of copper makes it a useful metal.
Determine the frequency of a photon that will cause the first ionization of copper. Use sections 1, 2 and 8 of the data booklet.
-
21M.2.hl.TZ2.2a(ii):
Explain why the first ionization energy of sulfur is lower than that of phosphorus.
- 22M.2.hl.TZ1.1e(iv): Suggest, giving a reason, whether magnesium or nitrogen would have the greater sixth...
-
21N.2.hl.TZ0.2b:
Sodium emits yellow light with a frequency of 5.09 × 1014 Hz when electrons transition from 3p to 3s orbitals.
Calculate the energy difference, in J, between these two orbitals using sections 1 and 2 of the data booklet.
Darling, D, n.d. D lines (of sodium). [online] Available at <https://www.daviddarling.info/encyclopedia/D/D_lines.html> [Accessed 6 May 2020].
- 21N.1.hl.TZ0.5: Which statement explains why the second ionization energy of aluminium is higher than the...
