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A Level H1 Chemistry Periodic Table Quiz

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Questions

A-Level Chemistry H1 Quiz - Periodic Table

Name: __________________________
Class: __________________________
Date: __________________________
Score: ________ / 40

Duration: 45 minutes
Total Marks: 40

Instructions:

Answer all questions.
Write your answers in the spaces provided.
The use of a scientific calculator is permitted.
Data Booklet values may be required; assume standard values if not provided.

Section A: Periodicity and Physical Properties (Questions 1–5)

1. The elements sodium (Na) to argon (Ar) constitute Period 3 of the Periodic Table.
Explain why the atomic radius decreases from sodium to chlorine.
[2]

2. Silicon has a much higher melting point ( $1414^\circ\text{C}$ ) than phosphorus ( $44^\circ\text{C}$ ).
Explain this difference in terms of structure and bonding.
[3]

3. Which of the following oxides is amphoteric?
[1]

A. $Na_2O$
B. $MgO$
C. $Al_2O_3$
D. $SO_2$

4. Describe the trend in electrical conductivity across Period 3 from sodium to aluminium. Explain this trend in terms of metallic bonding.
[3]

5. The first ionisation energy of sulfur is lower than that of phosphorus, despite sulfur having a higher nuclear charge.
Explain this anomaly.
[2]

Section B: Chemical Reactivity and Trends (Questions 6–10)

6. Write a balanced equation, including state symbols, for the reaction of sodium with water.
[2]

7. Magnesium reacts very slowly with cold water but vigorously with steam.
(a) Write the equation for the reaction of magnesium with steam.
[1]

(b) State one observable difference between the reaction with cold water and the reaction with steam.
[1]

8. Chlorine reacts with water to form an equilibrium mixture.
(a) Write the equation for this reaction.
[1]

(b) State the oxidation state of chlorine in each of the two chlorine-containing products formed.
[2]

Product 1: _______________
Product 2: _______________

9. Explain why the acidity of the chlorides changes from basic ( $NaCl$ ) to acidic ( $SiCl_4$ , $PCl_5$ ) across Period 3. Refer to the interaction with water in your answer.
[3]

10. Aluminium chloride ( $AlCl_3$ ) sublimes at a relatively low temperature ( $178^\circ\text{C}$ ) compared to sodium chloride ( $NaCl$ , $801^\circ\text{C}$ ).
Explain this difference in terms of the structure and bonding present in the solid state.
[3]

Section C: Group 2 and Group 17 Trends (Questions 11–15)

11. Which statement correctly describes the trend down Group 2 (Mg to Ba)?
[1]

A. The thermal stability of the nitrates decreases.
B. The solubility of the hydroxides decreases.
C. The reducing power of the elements increases.
D. The first ionisation energy increases.

12. Explain why the thermal stability of Group 2 carbonates increases down the group.
[3]

13. Chlorine displaces bromine from aqueous potassium bromide.
(a) Write the ionic equation for this reaction.
[1]

(b) State the colour change observed in the solution.
[1]

14. The boiling points of the hydrogen halides are:
HF ( $293 \text{ K}$ ), HCl ( $188 \text{ K}$ ), HBr ( $206 \text{ K}$ ), HI ( $238 \text{ K}$ ).
Explain why HF has a significantly higher boiling point than HCl, and why the boiling points increase from HCl to HI.
[4]

15. Silver nitrate solution is added to separate solutions of sodium chloride and sodium iodide, followed by dilute ammonia and then concentrated ammonia.
Complete the table below.
[4]

Halide	Precipitate Colour	Solubility in Dilute $NH_3$	Solubility in Conc. $NH_3$
Chloride ( $Cl^-$ )
Iodide ( $I^-$ )

Section D: Application and Synthesis (Questions 16–20)

16. An unknown Period 3 element, X, forms an oxide with the formula $XO_2$ . This oxide has a high melting point and does not conduct electricity when molten.
Identify element X and explain your reasoning.
[2]

Element: _______________
Reasoning: _________________________________________________________________

17. Consider the reactions of Period 3 oxides with acids and bases.
(a) Write the equation for the reaction of magnesium oxide with hydrochloric acid.
[1]

(b) Write the equation for the reaction of silicon dioxide with hot concentrated sodium hydroxide.
[1]

18. Explain why aluminium is considered a p-block element despite showing some metallic properties. Refer to its electronic configuration.
[2]

19. A student investigates the pH of $0.1 \text{ mol dm}^{-3}$ solutions of $NaCl$ , $MgCl_2$ , and $AlCl_3$ .
(a) Predict the approximate pH of the $AlCl_3$ solution.
[1]

pH: _______________

(b) Explain why the solution of $AlCl_3$ is acidic, including an equation for the reaction with water.
[3]

20. The table below shows the first ionisation energies (in $\text{kJ mol}^{-1}$ ) for three consecutive elements in Period 3:
Element P: 786
Element Q: 1012
Element R: 1000

(a) Identify elements P, Q, and R.
[1]

P: _______ Q: _______ R: _______

(b) Explain why the ionisation energy drops from Q to R.
[2]

End of Quiz

Answers

A-Level Chemistry H1 Quiz - Periodic Table (Answer Key)

1. [2 marks]

Nuclear charge increases (number of protons increases) [1].
Electrons are added to the same principal quantum shell (same shielding effect), so the attraction between the nucleus and outer electrons increases, pulling the shell closer [1].

2. [3 marks]

Silicon has a giant covalent (macromolecular) structure [1].
Strong covalent bonds extend throughout the lattice, requiring large amounts of energy to break [1].
Phosphorus exists as simple molecular structures ( $P_4$ ) held together by weak van der Waals forces, which require little energy to overcome [1].

3. [1 mark]
C. $Al_2O_3$

4. [3 marks]

Electrical conductivity increases from Na to Al [1].
The number of delocalised electrons per atom increases (Na: 1, Mg: 2, Al: 3) [1].
This results in stronger metallic bonding and a higher density of charge carriers, facilitating better conduction [1].

5. [2 marks]

In sulfur, the electron being removed is from a paired orbital ( $3p^4$ ) [1].
Spin-pair repulsion between the two electrons in the same orbital makes it easier to remove one electron compared to phosphorus, where the $3p$ electrons are unpaired [1].

6. [2 marks]
$2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g)$
[1 for correct species, 1 for balancing and state symbols]

7.
(a) [1 mark]
$Mg(s) + H_2O(g) \rightarrow MgO(s) + H_2(g)$
(b) [1 mark]
Reaction with steam produces a bright white light/flame, whereas reaction with cold water is very slow/barely visible (or produces bubbles very slowly).

8.
(a) [1 mark]
$Cl_2(aq) + H_2O(l) \rightleftharpoons HCl(aq) + HClO(aq)$
(b) [2 marks]
Product 1 (HCl): -1
Product 2 (HClO): +1

9. [3 marks]

NaCl is ionic; it dissolves to form neutral ions ( $Na^+$ , $Cl^-$ ) that do not hydrolyse significantly, so the solution is neutral/basic (oxide is basic) [1].
$SiCl_4$ and $PCl_5$ are simple covalent molecules [1].
They react vigorously with water (hydrolysis) to produce $HCl$ (and silicic/phosphoric acids), releasing $H^+$ ions, making the solution acidic [1].

10. [3 marks]

$NaCl$ has a giant ionic lattice structure with strong electrostatic forces of attraction between oppositely charged ions [1].
$AlCl_3$ (at low pressure/subliming conditions) exists as simple covalent molecules (dimers $Al_2Cl_6$ ) [1].
The intermolecular forces (van der Waals) between $AlCl_3$ molecules are much weaker than the ionic bonds in $NaCl$ , requiring less energy to sublime [1].

11. [1 mark]
C. The reducing power of the elements increases.

12. [3 marks]

As the group is descended, the size of the cation ( $M^{2+}$ ) increases [1].
The charge density of the cation decreases, leading to less polarisation of the carbonate ion ( $CO_3^{2-}$ ) [1].
Less polarisation means the C-O bonds are less weakened, making the carbonate more thermally stable [1].

13.
(a) [1 mark]
$Cl_2(aq) + 2Br^-(aq) \rightarrow 2Cl^-(aq) + Br_2(aq)$
(b) [1 mark]
Colourless/pale green to orange/brown.

14. [4 marks]

HF molecules form strong hydrogen bonds due to the high electronegativity of fluorine and the small size of the H atom [1].
HCl, HBr, and HI do not form hydrogen bonds; they are held by van der Waals forces [1].
Hydrogen bonds are much stronger than van der Waals forces, hence HF has a much higher BP [1].
From HCl to HI, the number of electrons increases, leading to stronger van der Waals forces (instantaneous dipole-induced dipole), so boiling points increase [1].

15. [4 marks]

Halide	Precipitate Colour	Solubility in Dilute $NH_3$	Solubility in Conc. $NH_3$
Chloride ( $Cl^-$ )	White	Soluble	Soluble
Iodide ( $I^-$ )	Yellow	Insoluble	Insoluble

(1 mark per correct cell)

16. [2 marks]

Element: Silicon (Si) [1].
Reasoning: $SiO_2$ is a giant covalent structure (high MP) and does not have free ions/electrons to conduct electricity [1].

17.
(a) [1 mark]
$MgO(s) + 2HCl(aq) \rightarrow MgCl_2(aq) + H_2O(l)$
(b) [1 mark]
$SiO_2(s) + 2NaOH(aq) \rightarrow Na_2SiO_3(aq) + H_2O(l)$

18. [2 marks]

Aluminium has the electronic configuration $[Ne] 3s^2 3p^1$ [1].
The highest energy electron is in a p-orbital, placing it in the p-block (Group 13) [1].

19.
(a) [1 mark]
pH: 3 (Accept 2–4)
(b) [3 marks]

$Al^{3+}$ is a small, highly charged cation with high charge density [1].
It polarises the water molecules in its hydration shell, weakening the O-H bonds [1].
Equation: $[Al(H_2O)_6]^{3+}(aq) + H_2O(l) \rightleftharpoons [Al(H_2O)_5(OH)]^{2+}(aq) + H_3O^+(aq)$ [1].

20.
(a) [1 mark]
P: Si (Silicon)
Q: P (Phosphorus)
R: S (Sulfur)
(Note: P=786, Q=1012, R=1000 matches Si, P, S data trends)
(b) [2 marks]

Sulfur (R) has a paired electron in the $3p$ orbital ( $3p^4$ ) [1].
Electron-electron repulsion in the paired orbital makes it easier to remove the electron compared to Phosphorus (Q) which has unpaired electrons ( $3p^3$ ) [1].