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2018 O Level Chem P1 Q9 — Metallic Bonding / Properties of Metals Solution

Metallic Bonding / Properties of Metals 2018 O Level Pure Chemistry · Paper 1 · Q9

Question

Copper is a metal. The structure of copper is described as a lattice of positive ions in a 'sea of electrons'. Which statements about copper are correct? 1 Copper conducts heat because the positive ions are free to move. 2 Copper conducts electricity because the electrons are free to move. 3 Copper ions are held together because of their attraction for each other. 4 Copper has a high melting point due to the strong covalent bonds.

A1, 2 and 3
B2, 3 and 4
C2 and 3 only
D2 only

Correct answer: D

Video Solution

Explanation

Answer: D (2 only). Copper has a metallic lattice: positive ions held together by their attraction to a sea of delocalised electrons.

Statement 1 is wrong: the positive ions are not free to move (they vibrate about fixed positions); heat is carried by the delocalised electrons. Statement 2 is correct: under a potential difference the delocalised electrons drift through the metal, so it conducts electricity. Statement 3 is wrong: like-charged ions repel, so the ions are held by attraction to the electron sea, not to each other. Statement 4 is wrong: the bonding is metallic, not covalent.

Only statement 2 is correct. Answer D.

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