Chemistry of selected elements: properties and reactions

Inorganic Chemistry: Chemistry of Selected Elements

Alkali Metals (Group 1)

⚡️ Alkali metals are the most reactive of all metals. Think of them as the extremely energetic friends who always want to share electrons to become stable.

• Low density, low melting points.
• Soft enough to be cut with a knife.
• Highly reactive with water: Na + H₂O → NaOH + ½ H₂↑
• Form +1 cations (e.g., Na⁺).

Example reaction with water (Li): 2 Li + 2 H₂O → 2 LiOH + H₂↑

1. Write the balanced equation.
2. Identify the oxidation state change.
3. Predict the gas produced.

Alkaline Earth Metals (Group 2)

🧪 These metals are a bit less “hyperactive” than alkali metals but still love to lose two electrons.

• Higher melting points than alkali metals.
• Form +2 cations (e.g., Ca²⁺).
• React with water slowly: Mg + 2 H₂O → Mg(OH)₂ + H₂↑

Reaction with acids: Ca + 2 HCl → CaCl₂ + H₂↑

Transition Metals

🔬 Transition metals are the “versatile artists” of the periodic table, capable of many oxidation states.

• Often form coloured solutions.
• Common oxidation states: +2, +3, +4.
• Example: Fe²⁺ ↔ Fe³⁺ in redox reactions.

Redox example: Fe²⁺ + Cu²⁺ → Fe³⁺ + Cu⁺

1. Identify the species being oxidised and reduced.
2. Balance the electrons transferred.
3. Check charge and mass balance.

Halogens (Group 17)

💡 Halogens are the “stubborn friends” that love to gain one electron to complete their outer shell.

• High electronegativity.
• Form -1 anions (e.g., Cl⁻).
• Reactivity decreases down the group.

Reaction with metals: 2 Cl₂ + 2 Na → 2 NaCl + Cl₂↑

Redox with oxygen: Cl₂ + H₂O → HCl + HClO

Noble Gases (Group 18)

🌌 Noble gases are the “lonely stars” that rarely react because their outer shells are full.

• Inert under normal conditions.
• Used in lighting (Neon) and as inert atmospheres.
• Can form compounds under extreme conditions (e.g., XeF₂).

Example: Xe + 2 F₂ → XeF₂

Summary Table of Selected Elements