Materials: Metals and Non-Metals Full Chapter Class 8 Science | NCERT Science Class 8 Chapter 4

Magnet Brains2 minutes read

Metals and nonmetals are classified based on their properties and uses, including the creation of alloys and reactions with oxidants and water. The distinction is made through physical and chemical properties, with common examples like copper for wires and sodium reacting with water to form sodium hydroxide.

Insights

  • Metals and nonmetals are classified based on their distinct physical and chemical properties, with metals like copper being malleable and commonly used for wires, while nonmetals like sulfur have unique properties.
  • The reactions of metals and nonmetals with oxidants and water showcase their differing behaviors, such as sodium reacting vigorously with water to form sodium hydroxide, and the production of hydrogen gas when metals react with acids, highlighting the fundamental disparities between the two material categories.

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Recent questions

  • What are the differences between metals and nonmetals?

    Metals and nonmetals are distinguished by their properties and uses. Metals like gold and silver can be mixed to create alloys, while nonmetals like sulfur and oxygen have distinct properties. Physical and chemical properties differentiate metals and nonmetals, with metals such as copper being commonly used for wires due to their malleability. Nonmetals do not release hydrogen gas when reacting with acids, unlike metals.

  • How do metals react with water and oxidants?

    Metals like sodium react vigorously with water, forming sodium hydroxide. When metals react with water, they release hydrogen gas. In the case of metals reacting with oxidants, they form various compounds like sodium hydroxide. The chapter explores the chemical reactions of metals with water and oxidants, showcasing the distinct behavior of metals in these reactions.

  • What are some common metals and their uses?

    Common metals like iron, copper, aluminum, calcium, and magnesium are discussed in the chapter. These metals have specific uses such as iron in machinery, copper in wires, and aluminum in foil for wrapping food items. Each metal has unique properties that make them suitable for various applications, ranging from construction to electrical conductivity.

  • How are displacement reactions demonstrated in metals?

    Displacement reactions are showcased in the chapter through experiments involving metals replacing other metals in reactions. For example, zinc displaces copper in a copper sulphate solution, demonstrating the reactivity and displacement properties of metals. These reactions help illustrate the differences in behavior between various metals when exposed to different compounds.

  • Why are nonmetals like sulfur and oxygen important?

    Nonmetals like sulfur and oxygen play crucial roles in chemical reactions and natural processes. They have distinct properties that make them essential for various applications, such as oxygen's role in respiration and sulfur's presence in compounds like sulfuric acid. Understanding the properties and behavior of nonmetals is vital for comprehending their significance in both scientific and practical contexts.

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Summary

00:00

Metals vs Nonmetals: Properties and Reactions

  • The chapter discusses the classification of materials into metals and nonmetals.
  • Metals and nonmetals are distinguished by their properties and uses.
  • Metals like gold and silver can be mixed to create alloys.
  • Physical and chemical properties differentiate metals and nonmetals.
  • Copper is a common metal used for wires due to its malleability.
  • Iron, copper, aluminum, calcium, and magnesium are common metals.
  • Nonmetals like sulfur and oxygen have distinct properties.
  • Chemical reactions of metals and nonmetals with oxidants and water are explored.
  • Sodium reacts vigorously with water, forming sodium hydroxide.
  • Metals release hydrogen gas when reacting with acids, while nonmetals do not.

25:02

Chemical reactions and properties of metals

  • To create hydrogen gas, dilute sulfuric acid is used with argent, which is a ten plus two lickati acid.
  • The gas is obtained by delivering it from the solution, resulting in a soft spot and a release of hydrogen gas.
  • In an experiment involving metals and nonmetals, test tubes are used to observe reactions with Hydrochloric Acid and sulfur.
  • Displacement reactions are demonstrated by metals replacing other metals in reactions, such as zinc displacing copper in copper sulphate solution.
  • The distinction between metals and nonmetals is based on appearance and properties like conductivity and reactivity.
  • Aluminum foil is used to wrap food items due to its non-reactive nature with acidic foods like lemon pickle.
  • Various metals like gold, iron, carbon, and copper have specific uses in jewelry, machinery, fuel, and electric wires.
  • Testing the nature of gases involves experiments like observing carbon dioxide formation and testing acidity with litmus paper.
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