Question 17N.2.sl.TZ0.2
| Date | November 2017 | Marks available | [Maximum mark: 11] | Reference code | 17N.2.sl.TZ0.2 |
| Level | sl | Paper | 2 | Time zone | TZ0 |
| Command term | Deduce, Describe, Draw, Explain, Identify, Label, State | Question number | 2 | Adapted from | N/A |
Trends in physical and chemical properties are useful to chemists.
Explain the general increasing trend in the first ionization energies of the period 3 elements, Na to Ar.
[2]
increasing number of protons
OR
increasing nuclear charge
«atomic» radius/size decreases
OR
same number of shells
OR
similar shielding «by inner electrons»
«greater energy needed to overcome increased attraction between nucleus and electrons»
Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group.
[2]
atomic/ionic radius increases
smaller charge density
OR
force of attraction between metal ions and delocalised electrons decreases
Do not accept discussion of attraction between valence electrons and
nucleus for M2.
Accept “weaker metallic bonds” for M2.
State an equation for the reaction of phosphorus (V) oxide, P4O10 (s), with water.
[1]
P4O10 (s) + 6H2O (l) → 4H3PO4 (aq)
Accept “P4O10 (s) + 2H2O (l) → 4HPO3 (aq)” (initial reaction).
Describe the emission spectrum of hydrogen.
[2]
«series of» lines
OR
only certain frequencies/wavelengths
convergence at high«er» frequency/energy/short«er» wavelength
M1 and/or M2 may be shown on a diagram.
The Activity series lists the metal in order of reactivity.
Identify the strongest reducing agent in the given list.
[1]
Mn
A voltaic cell is made up of a Mn2+/Mn half-cell and a Ni2+/Ni half-cell.
Deduce the equation for the cell reaction.
[1]
Mn (s) + Ni2+ (aq) → Ni (s) + Mn2+ (aq)
The voltaic cell stated in part (ii) is partially shown below.
Draw and label the connections needed to show the direction of electron movement and ion flow between the two half-cells.
[2]
wire between electrodes AND labelled salt bridge in contact with both electrolytes
anions to right (salt bridge)
OR
cations to left (salt bridge)
OR
arrow from Mn to Ni (on wire or next to it)
Electrodes can be connected directly or through voltmeter/ammeter/light bulb, but not a battery/power supply.
Accept ions or a specific salt as the label of the salt bridge.