9.3 AS Level

Chemical periodicity of other elements

Cambridge A-Level Chemistry (9701)  · Unit 9: The Periodic Table: chemical periodicity  · 8 flashcards

Chemical periodicity of other elements is topic 9.3 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 9 — The Periodic Table: chemical periodicity .  In one line: The solubility of Group 2 hydroxides increases down the group. Mg(OH)₂ is sparingly soluble, while Ba(OH)₂ is significantly more soluble.

Marked as AS Level: examined at AS Level in Paper 1 (Multiple Choice), Paper 2 (AS Structured Questions) and Paper 3 (Advanced Practical Skills). The same content may also be assumed in Paper 4 (A Level Structured Questions).

The deck below contains 8 flashcards — 2 definitions, 4 key concepts and 2 calculations — covering the precise wording mark schemes reward.  Use the 2 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.

Key definition

Trend in solubility of Group 2 hydroxides in water

The solubility of Group 2 hydroxides increases down the group. Mg(OH)₂ is sparingly soluble, while Ba(OH)₂ is significantly more soluble.

What the Cambridge 9701 syllabus says

Official 2025-2027 spec · AS Level

These are the exact learning outcomes Cambridge sets for this topic. The candidate is expected to be able to do each of these on the relevant paper.

  1. predict the characteristic properties of an element in a given group by using knowledge of chemical periodicity
  2. deduce the nature, possible position in the Periodic Table and identity of unknown elements from given information about physical and chemical properties
  3. describe, and write equations for, the reactions of the elements with oxygen, water and dilute hydrochloric and sulfuric acids
  4. describe, and write equations for, the reactions of the oxides, hydroxides and carbonates with water and dilute hydrochloric and sulfuric acids
  5. describe, and write equations for, the thermal decomposition of the nitrates and carbonates, to include the trend in thermal stabilities
  6. describe, and make predictions from, the trends in physical and chemical properties of the elements involved in the reactions in 10.1.1 and the compounds involved in 10.1.2, 10.1.3 and 10.1.5
  7. state the variation in the solubilities of the hydroxides and sulfates
  8. describe the colours and the trend in volatility of chlorine, bromine and iodine
  9. describe and explain the trend in the bond strength of the halogen molecules
  10. interpret the volatility of the elements in terms of instantaneous dipole–induced dipole forces

Cambridge syllabus keywords to use in your answers

These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.

chemical periodicity atomic radius ionic radius melting point electrical conductivity

Tips to avoid common mistakes in Chemical periodicity of other elements

Key Concept Flip

How does electronegativity change down Group 2 (alkaline earth metals), and what effect does this have on the reactivity with water?

Answer Flip

Electronegativity decreases down Group 2. This leads to a greater ionic character in the metal-oxygen or metal-hydrogen bond in the oxide or hydroxide. As a result, reactivity with water increases down the group (

Example: Mg reacts slowly, Ca reacts faster, Sr and Ba react readily).
Key Concept Flip

Describe the trend in thermal stability of Group 2 carbonates.

Answer Flip

Thermal stability increases down Group 2 carbonates (MgCO₃ < CaCO₃ < SrCO₃ < BaCO₃). This is because the larger the cation (

Example: Ba²⁺), the less it polarizes the carbonate anion (CO₃²⁻), making it more difficult to decompose.
Calculation Flip

Write a balanced equation for the reaction of strontium with oxygen.

Answer Flip

2Sr(s) + O₂(g) → 2SrO(s)

Definition Flip

State the trend in solubility of Group 2 hydroxides in water.

Answer Flip

The solubility of Group 2 hydroxides increases down the group. Mg(OH)₂ is sparingly soluble, while Ba(OH)₂ is significantly more soluble.

Key Concept Flip

Describe the trend in volatility of the halogens (Cl₂, Br₂, I₂).

Answer Flip

Volatility decreases down the halogens (Cl₂ > Br₂ > I₂). This is because the strength of instantaneous dipole-induced dipole forces (van der Waals forces) increases with increasing number of electrons and molecular size.

Key Concept Flip

Explain the trend in bond strength of halogen molecules (Cl₂, Br₂, I₂).

Answer Flip

Bond strength decreases down the halogens (Cl₂ > Br₂ > I₂). This is due to increased bond length and decreased orbital overlap as the atomic size of the halogen increases.

Definition Flip

What are the colours of chlorine, bromine, and iodine at room temperature and pressure?

Answer Flip

Chlorine (Cl₂) is a pale green gas. Bromine (Br₂) is a reddish-brown liquid. Iodine (I₂) is a dark grey/purple solid.

Calculation Flip

Write a balanced equation for the thermal decomposition of magnesium nitrate.

Answer Flip

2Mg(NO₃)₂(s) → 2MgO(s) + 4NO₂(g) + O₂(g)

More Chemistry flashcards

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8.3 Homogeneous and heterogeneous catalysts 11.2 The chemical properties of the halogen elements and the hydrogen halides

Key terms covered in this Chemical periodicity of other elements deck

Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.

Trend in solubility of Group 2 hydroxides in water
The colours of chlorine, bromine, and iodine at room temperature and pressure

How to study this Chemical periodicity of other elements deck

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