Page 1: Alkali Metals and Alkaline Earth Metals

This page focuses on the properties and reactions of alkali metals (lithium, sodium, potassium) and alkaline earth metals (beryllium, calcium, strontium, barium). It covers their reactions with oxygen, formation of hydroxides, and characteristic tests.

Highlight: Alkali metals are highly reactive, forming oxides, peroxides, and superoxides when exposed to oxygen.

The Blok s elements, particularly lithium, sodium, and potassium, demonstrate increasing reactivity down the group. Their reactions with oxygen produce different products:

• Lithium forms lithium oxide (Li₂O)
• Sodium forms sodium peroxide (Na₂O₂)
• Potassium forms potassium superoxide (KO₂)

Example: 2Na + O₂ → Na₂O₂ (sodium peroxide formation)

The page also discusses the Trommer's test, which involves the reaction of copper(II) hydroxide with reducing sugars, resulting in a color change.

Vocabulary: Hygroscopic - A substance that readily absorbs moisture from the air.

Alkaline earth metals, including beryllium, calcium, strontium, and barium, are discussed in terms of their oxides and hydroxides. Beryllium oxide and hydroxide exhibit amphoteric properties, while the others are basic.

Definition: Amphoteric - A substance that can act as both an acid and a base.

The chemical activity of alkaline earth metals increases down the group, with calcium carbonate being a significant compound found in limestone.

Example: CaCO₃ + CO₂ + H₂O → Ca(HCO₃)₂ (formation of calcium bicarbonate in hard water)