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MHT-CET Chemistry · Elements of Group 1 and 2

Group 2: The Alkaline Earth Metals and Beryllium's Anomalies

The alkaline earth metals Be, Mg, Ca, Sr, Ba and Ra form +2 ions; beryllium, much smaller than the rest, behaves unlike its group — it does not react with water, its oxide is amphoteric, and it resembles aluminium diagonally.

All Elements of Group 1 and 2 notesMHT-CET Chemistry strategy

Why this matters

11 PYQs, one MODERATE. Seven are about beryllium's odd behaviour — the diagonal relationship, water, amphoteric BeO, the soluble fluoride; four are the other metals — magnesium burning in air, quicklime, the ammonia solution, and naming a group-2 metal. Two cards.

Concept 1 of 2: Beryllium: the Anomalous First Member

Be²⁺ is tiny and highly charged, so it polarises strongly and bonds partly covalently. That one fact makes beryllium unreactive to water, its oxide amphoteric, its fluoride soluble, and its chemistry like aluminium's (similar charge-to-radius ratio) — the diagonal relationship.

Definition

  • Diagonal relationship: Be ↔ Al (and Li ↔ Mg).
  • Water: Be does not react even when hot (protective oxide film); Mg reacts with hot water; Ca, Sr, Ba with cold.
  • BeO is amphoteric: with HCl → BeCl₂; with NaOH → Na₂BeO₂ (sodium beryllate).
  • Fluorides: BeF₂ is very soluble (high hydration energy); MgF₂, CaF₂, SrF₂ are sparingly soluble.
PropertyBerylliumRest of group 2
Diagonal partnerAl—Q
Reaction with waterNone, even hotMg hot; Ca, Sr, Ba coldQ
OxideAmphoteric: BeCl₂ / Na₂BeO₂BasicQ
FluorideBeF₂ solubleSparingly solubleQ
Practice this conceptself-check · 3 quick reps

The same idea in a real exam question:

MHT-CET · 2023 · 16th May Shift 2 · Q79Moderate

Example 1 · Elements of Group 1 and 2 · Group 2 Alkaline Earth Metals, Properties and Reactivity

What products are obtained when beryllium oxide is treated separately with aq. HCl and aq. NaOH solutions respectively?

Writing the beryllate as Na₂BeO₄

Be is +2: Na₂BeO₂ balances (2 − 4 + 2 = 0). Na₂BeO₄ is offered as a formula that looks like sulphate but cannot balance.
Drill 6 more on beryllium: the anomalous first member

Concept 2 of 2: Magnesium, Calcium and the Ammonia Solution

Magnesium is reactive enough to combine with the nitrogen of air as well as its oxygen, so burning it gives two products. Calcium carbonate heated gives quicklime. And like group 1, the heavier group-2 metals dissolve in liquid ammonia with a deep blue-black colour.

Definition

  • Group 2: Be, Mg, Ca, Sr, Ba, Ra (Rb, Cs, Fr are group 1).
  • Mg burns in air: MgO and Mg₃N₂.
  • Quicklime: CaCO₃ → CaO + CO₂ (heating limestone).
  • In liquid ammonia: deep blue-black solutions.
QuestionAnswer
Product of Mg burning in airMgO and Mg₃N₂Q
Raw material for quicklimeCalcium carbonateQ
Colour in liquid NH₃Deep blue-blackQ
Practice this conceptself-check

The same idea in a real exam question:

MHT-CET · 2025 · 21 April Shift I · Q95Easy

Example 2 · Elements of Group 1 and 2 · Group 2 Alkaline Earth Metals, Properties and Reactivity

Identify the product when magnesium burns in air.

MgO only

Air is mostly nitrogen, and magnesium burns in it too — the answer is MgO AND Mg₃N₂.
Drill 3 more on magnesium, calcium and the ammonia solution

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Reference tables (2)

Beryllium: the Anomalous First Member4 rows
PropertyBerylliumRest of group 2
Diagonal partnerAl—Q
Reaction with waterNone, even hotMg hot; Ca, Sr, Ba coldQ
OxideAmphoteric: BeCl₂ / Na₂BeO₂BasicQ
FluorideBeF₂ solubleSparingly solubleQ
Magnesium, Calcium and the Ammonia Solution3 rows
QuestionAnswer
Product of Mg burning in airMgO and Mg₃N₂Q
Raw material for quicklimeCalcium carbonateQ
Colour in liquid NH₃Deep blue-blackQ

Watch out for (2)

Test yourself on Elements of Group 1 and 2

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