Class 12 Chemistry Chapter 13 s and p – Block Element – Notes

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Chapter 1: The s-Block and p-Block Elements

In the 12th-grade Chemistry syllabus, Chapter 1 focuses on the s-block and p-block elements, which are crucial parts of the periodic table. This chapter delves into the characteristics, properties, and reactions of these elements.

s-Block Elements

  1. Group 1: Alkali Metals
  • Comprising lithium, sodium, potassium, rubidium, cesium, and francium.
  • These metals are highly reactive, especially with water, producing hydroxides and hydrogen gas.
  • They have a single electron in their outermost shell, leading to similar chemical properties.
  • They are characterized by their low ionization enthalpies, which decrease down the group.
  1. Group 2: Alkaline Earth Metals
  • Includes beryllium, magnesium, calcium, strontium, barium, and radium.
  • These metals are less reactive than alkali metals but still react with water and oxygen.
  • They have two electrons in their outermost shell and tend to lose these electrons to form divalent cations.
  • Their ionization enthalpies are higher than those of alkali metals but decrease down the group.

p-Block Elements

  1. Group 13: The Boron Family
  • Consists of boron, aluminum, gallium, indium, and thallium.
  • Boron, being a metalloid, exhibits different properties compared to the other members, which are metals.
  • These elements have three electrons in their outer shell and form trivalent compounds.
  1. Group 14: The Carbon Family
  • Includes carbon, silicon, germanium, tin, and lead.
  • Carbon is a non-metal, silicon and germanium are metalloids, and tin and lead are metals.
  • They exhibit a wide range of oxidation states and form covalent bonds.
  1. Group 15: The Nitrogen Family
  • Comprising nitrogen, phosphorus, arsenic, antimony, and bismuth.
  • These elements have five electrons in their outermost shell, making them capable of forming three covalent bonds.
  • They display allotropy and exhibit multiple oxidation states.
  1. Group 16: The Oxygen Family
  • Also known as the chalcogens, this group includes oxygen, sulfur, selenium, tellurium, and polonium.
  • Oxygen is a vital component for life, while sulfur is known for its diverse chemistry.
  • These elements typically form -2 oxidation states and have a tendency to gain electrons.
  1. Group 17: The Halogens
  • Comprising fluorine, chlorine, bromine, iodine, and astatine.
  • These are highly reactive non-metals with seven electrons in their outer shell.
  • They are known for forming salts when combined with metals.
  1. Group 18: The Noble Gases
  • Includes helium, neon, argon, krypton, xenon, and radon.
  • These gases are characterized by their complete valence electron shells, making them very stable and unreactive.
  • They are used in various applications, including lighting and inert environments.

Key Concepts and Reactions

  • The chapter covers the trends in the periodic table, such as atomic and ionic radii, ionization enthalpy, electron gain enthalpy, and electronegativity.
  • It also discusses the unique properties of elements and their compounds, the anomalous behavior of the first element in each group, and the diagonal relationship.
  • The chemical reactivity and trends within each group are explored, along with important compounds and their uses.

This chapter is foundational for understanding the chemistry of s-block and p-block elements, their reactions, and their applications in various industries.

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