Group 1 (Alkali Metals)

Overview of Group 1 (Alkali Metals)

  • Located in the first group of the periodic table.
  • Contains elements such as lithium, sodium, potassium, rubidium, caesium and francium.
  • Have one electron in their outermost shell which they readily lose, creating a +1 ion.
  • Follow a pattern of physical and chemical properties which is known as group trends.

Physical Properties

  • Are soft and can be easily cut with a knife.
  • Have low densities (lithium, sodium and potassium can float on water).
  • Possess a shiny metallic appearance but tarnish rapidly in air due to the formation of oxide layers.
  • From lithium to francium, melting point, boiling point and hardness decrease, while atomic radius and relative atomic mass increase.

Chemical Properties

  • React vigorously with water, producing hydrogen gas and alkaline solutions (solutions that have a pH greater than 7).
  • Reactivity increases down the group, i.e., francium is the most reactive and lithium the least.
  • Form alkali metal oxides when burnt in oxygen.

Reactions with Non-metals

  • React with halogens (group 7 elements) to form ionic halides.
  • React with oxygen to form oxides, peroxides and superoxides depending on the nature of the metal.
  • React with nitrogen to form metal nitrides.

Uses of Alkali Metals

  • Sodium and potassium are essential components of biological systems.
  • Lithium, sodium and potassium are important for the production of glass and ceramics.
  • Sodium and potassium compounds are used in fertilizers.
  • Potassium and sodium are important in the process of nerve transmission.

Health and Safety Considerations

  • Must be handled carefully as they are highly reactive.
  • Always stored in oil to prevent them from coming into contact with air or water.
  • Protective clothing and eye protection are required when handling these metals.

Overall, the alkali metals are a fascinating group of elements that demonstrate key principles of inorganic chemistry. Spending time understanding the properties, trends and uses of these elements is a crucial foundation in grasifying inorganic chemistry.