Question
Zinc metal contains metallic bonding. Which is the best description of a metallic bond?
A. The electrostatic attraction between a pair of electrons and positively charged nuclei.
B. The electrostatic attraction between oppositely charged ions.
C. The electrostatic attraction between a lattice of positive ions and delocalized electrons.
D. The bond formed when one atom provides both electrons in a shared pair.
Answer/Explanation
Markscheme
C
Question
Which series shows the correct order of metallic bond strength from strongest to weakest?
A Na > K > Rb > Mg
B Mg > Rb > K > Na
C Rb > K > Na > Mg
D Mg > Na > K > Rb
Answer/Explanation
Ans: D
Question
Which substance does not conduct electricity?
A. Solid zinc
B. Molten zinc
C. Solid zinc chloride
D. Molten zinc chloride
Answer/Explanation
Markscheme
C
Examiners report
Question
Which particles are responsible for electrical conductivity in metals?
A. Anions
B. Cations
C. Electrons
D. Protons
Answer/Explanation
Markscheme
C
Examiners report
One G2 comment stated that the terms cation and anion are not stated on the syllabus. Although strictly correct, it would be assumed that these terms would be introduced to students in the classroom as they are universally used in chemistry (e.g. even the term carbocation is widely used in explaining certain nucleophilic substitution reaction mechanisms).
Question
Which particles are responsible for the conduction of electricity in molten aluminium?
A. Cations
B. Anions
C. Electrons
D. Protons
Answer/Explanation
Markscheme
C
Examiners report
There were a number of comments on this question and many teachers stated that although they assumed that the required answer was C. i.e. electrons, many felt that as molten aluminium was involved, the cations are mobile and thus could conduct electricity, so A. could be another answer. Although the correct answer C. (electrons) was given by the majority of candidates (71.18%), it was decided at Grade Award to also accept A. as clearly some candidates may have approached the question in the sense articulated by several teachers.