Alkali Metals

=====================

Definition

The alkali metals are a group of highly reactive, silvery-white metals located in the first column of the Periodic Table. They are highly electropositive and readily lose one electron to form a positive ion.

History

The discovery of the alkali metals dates back to 1815 when Sir Humphry Davy used an electric current to extract metallic hydrogen from a sample of caustic soda (Sodium hydroxide). He isolated several of these metals, including Lithium, Sodium, Potassium, Rubidium, cesium, and Francium.

Properties

The alkali metals have the following properties:

• Physical State: Alkali metals are highly reactive gases at room temperature.
• Appearance: The alkali metals have a silvery-white appearance.
• Electrical Conductivity: Alkali metals are excellent conductors of electricity.
• Melting Points:
  • Lithium: 180.56°C (356.9°F)
  • Sodium: 265.83°C (498.3°F)
  • Potassium: 769.73°C (1404.1°F)
  • Rubidium: 852.67°C (1566.17°F)
  • Caesium: 0273°C (4805.7°F)
  • Francium: 327.45°C (617.3°F)
• Density: The alkali metals have a high density.
• Reactivity: Alkali metals are highly reactive and readily lose one electron to form a positive ion.

Classification

The alkali metals can be classified into three categories:

• Lithium group:
  • Lithium (Li)
  • Sodium (Na)
  • Potassium (K)
  • Rubidium (Rb)
  • Caesium (Cs)
  • Francium (Fr)
• Potassium group:
  • Rubidium (Rb)
  • Caesium (Cs)
  • Francium (Fr)
• Sodium group:
  • Sodium (Na)

Occurrence

The alkali metals occur naturally as follows:

• Lithium: Lithium is found in small amounts in hydroxide minerals such as spatholite and petalite.
• Sodium: Sodium is found in large deposits of Sodium carbonate, Sodium chloride, and Sodium sulfate.
• Potassium: Potassium is found in small deposits of Potassium carbonate, Potassium chloride, and Potassium sulfates.
• Rubidium: Rubidium is found in very rare minerals such as Rubidium phosphate and Rubidium carbonates.
• Caesium: Caesium is found in small amounts in hydroxide minerals such as spatholite and petalite.
• Francium: Francium is a highly radioactive and difficult to extract mineral called francite.

Uses

The alkali metals have several uses:

• Electronics: Alkali metals are used in the production of electronic components such as batteries, capacitors, and semiconductors.
• Chemicals: Alkali metals are used in the production of chemicals such as Sodium hydroxide (caustic soda) and Potassium chloride.
• Glassmaking: Alkali metals are used in the production of glass.

Safety

The alkali metals have several safety concerns:

• Flammability: Alkali metals are highly flammable and should be handled with caution.
• Corrosiveness: Alkali metals are highly corrosive and can cause severe burns if not handled properly.
• Radioactivity: Francium is a highly radioactive metal that requires special handling and storage.

References

• “Alkali Metals” by the Periodic Table of Elements. [Online] Available: Elements/alkali-metal.php>
• “The Alkali Metals” by Encyclopedia Britannica. [Online] Available: https://www.britannica.com/element/alkali-metal
• “Alkali Metals” by the International Union of Pure and Applied Chemistry (IUPAC). [Online] Available: IUPAC.org/home/Elements/chemical-Elements/alkali-metals>