9.3 AS Level

Chemical periodicity of other elements

8 flashcards to master this topic

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)

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