Chemistry 9701 · AS & A Level · The Periodic Table: chemical periodicity

The Periodic Table: chemical periodicity — practice question

Table 2.1 presents the chlorides of a number of Period 3 elements.
(a)[4]

Complete Table 2.1. For each chloride, identify the bonding present under standard conditions (use C = covalent, I = ionic, M = metallic). For each chloride, identify the structure present under standard conditions (use G = giant, S = simple). Work out the oxidation state of the Period 3 element in each chloride.

(b)[3]

Write equations for the reactions of $\text{NaCl}$ and $\text{PCl}_5$ with water. Include state symbols in both equations.

(c(i))[2]

In the gas phase, $\text{AlCl}_3(g)$ is in equilibrium with $\text{Al}_2\text{Cl}_6(g)$ as shown: $2\text{AlCl}_3(g) \rightleftharpoons \text{Al}_2\text{Cl}_6(g)\; , \; \Delta H_r = -63\,\text{kJ mol}^{-1}$. Complete the dot-and-cross diagram to show the bonding in $\text{Al}_2\text{Cl}_6$.

(c(ii))[1]

State the effect of an increase in temperature on the equilibrium mixture in equation 1. Explain your answer.

(d)[3]

A $3.30\,\text{g}$ sample of a Period 3 chloride is heated to $500\,\text{K}$ in a sealed flask. At this temperature, the chloride is a gas occupying $250\,\text{cm}^3$ and the pressure inside the flask is $323\,\text{kPa}$. Use the ideal gas equation $pV = nRT$ to calculate the $M_r$ of the Period 3 chloride. Deduce its formula.

(e(i))[2]

An excess of $\text{Cl}^-(aq)$ is added to $1\,\text{cm}^3$ of $\text{Br}_2(aq)$. Describe what is observed. Explain your answer.

(e(ii))[2]

$\text{SCl}_2$ has $M_r = 103.1$ and is a liquid at room temperature. $\text{SBr}_2$ has $M_r = 191.9$ and is a gas at room temperature. Explain why the physical states of $\text{SCl}_2$ and $\text{SBr}_2$ are different. Give your answer in terms of intermolecular forces.

(f(i))[2]

Bismuth is a dense metal in the same group as phosphorus. Draw a labelled diagram to show the bonding in bismuth metal.

(f(ii))[2]

Bismuth reacts with chlorine to form $\text{BiCl}_3$. $\text{BiCl}_3$ is a solid at room temperature. It melts when heated gently. $\text{BiCl}_3$ reacts vigorously with water at room temperature to form an acidic solution. Suggest the type of bonding and structure shown by $\text{BiCl}_3$. Explain your answer.

Worked solution & mark scheme

This 21-mark question has a full step-by-step worked solution and mark scheme. One marking point: Right type of structure for NaCl, AlCl$_3$, SiCl$_4$, PCl$_5$

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