Site logo
    Add a listing
    Add a listing

    Study Material on “Metals and Non-metals” with Answers

    Q1: What are the general physical properties of metals?

    • Answer: Metals are generally shiny, malleable (can be hammered into thin sheets), ductile (can be drawn into wires), and are good conductors of heat and electricity. They are also usually solid at room temperature, with the exception of mercury (Hg), which is a liquid.

    Q2: How do metals react with oxygen, and what is formed?

    • Answer: Metals react with oxygen to form metal oxides. This reaction is known as oxidation. For example, when iron reacts with oxygen and water, it forms iron oxide (rust):
      [4Fe + 3O_2 + 6H_2O → 4Fe(OH)_3]
      [4Fe(OH)_3 → 2Fe_2O_3 + 6H_2O + O_2]

    Q3: Describe a property that distinguishes non-metals from metals.

    • Answer: Non-metals are generally poor conductors of heat and electricity, which contrasts with the high conductivity of metals. Non-metals can be solid, liquid, or gas at room temperature, and solid non-metals are brittle, not malleable or ductile.

    Q4: Give an example of how a metalloid behaves as a semi-conductor.

    • Answer: Silicon (Si), a metalloid, is a notable example of a semiconductor. It does not conduct electricity as well as metals but conducts it better than non-metals. This property makes silicon invaluable in the manufacture of electronic devices, including transistors, solar cells, and microchips.

    Q5: What is the environmental impact of metal extraction?

    • Answer: Metal extraction, especially through mining and refining processes, can have significant environmental impacts, including habitat destruction, water pollution with heavy metals and acids, and air pollution due to the release of toxic gases. Sustainable practices and recycling are critical to mitigating these effects.

    Q6: Explain the process of electrolysis in the context of metal extraction.

    • Answer: Electrolysis is a process used to extract metals from their ores. During electrolysis, an electric current is passed through an electrolyte solution containing the metal ion. This causes the metal ions to gain electrons (reduction) and be deposited at the cathode as pure metal, while non-metal ions lose electrons (oxidation) at the anode. For example, in the electrolysis of alumina (Al2O3) to extract aluminum:
      At the cathode: (Al^{3+} + 3e^- → Al)
      At the anode: (2O^{2-} → O_2 + 4e^-)

    Q7: How do metals and non-metals react to form salts?

    • Answer: Metals react with non-metals to form ionic compounds, commonly known as salts. In these reactions, metals lose electrons to become positively charged ions (cations), while non-metals gain electrons to become negatively charged ions (anions). The attraction between these oppositely charged ions forms the ionic bond in the salt. For example, sodium (Na), a metal, reacts with chlorine (Cl), a non-metal, to form sodium chloride (NaCl), a common salt:
      [2Na + Cl_2 → 2NaCl]

    Q8: Why are alloys considered important in technology and industry?

    • Answer: Alloys, which are mixtures of metals or a metal and a non-metal that behaves like a metal, are important because they possess enhanced properties compared to their component elements. For instance, steel, an alloy of iron (Fe) and carbon (C), is stronger and more durable than pure iron. Alloys are crucial in technology and industry for constructing buildings, vehicles, machinery, and in electronics because of their improved strength, durability, corrosion resistance, and electrical conductivity.

    Q9: What is the role of non-metals in living organisms?

    • Answer: Non-metals play crucial roles in the biochemistry of living organisms. For example, oxygen (O) is essential for respiration, carbon (C) is the key element in all organic life forms, forming the backbone of organic molecules like carbohydrates, proteins, and fats. Nitrogen (N) is a fundamental component of amino acids and nucleic acids (DNA and RNA). Phosphorus (P) is part of ATP, the energy currency of the cell, and also of nucleic acids.

    Q10: Explain the term ‘amphoteric oxide’ with examples.

    • Answer: Amphoteric oxides are oxides that can behave as both acids and bases in chemical reactions. This means they can react with both acids and bases to produce salts and water. An example of an amphoteric oxide is aluminum oxide (Al2O3). It reacts with hydrochloric acid (an acid) to form aluminum chloride (a salt) and water:
      [Al_2O_3 + 6HCl → 2AlCl_3 + 3H_2O]
      And it reacts with sodium hydroxide (a base) to form sodium aluminate (a salt) and water:
      [Al_2O_3 + 2NaOH + 3H_2O → 2NaAl(OH)_4]

    Q11: How can metals be recycled, and what are the benefits?

    • Answer: Metals can be recycled by collecting and processing metal waste and scrap into usable metal through various physical and chemical processes. Recycling metals saves energy, reduces mining waste, conserves natural resources, and decreases pollution. For example, recycling aluminum requires 95% less energy than producing it from raw bauxite ore. The benefits of metal recycling include sustainability, economic efficiency, and environmental protection.

    Study Material on “Chemical Properties of Metals and Non-metals”

    Reactivity Series and Displacement Reactions:

    • Q12: What is the reactivity series and how does it determine the outcome of displacement reactions?
    • Answer: The reactivity series is a list of metals arranged in order of decreasing reactivity. Metals higher in the series can displace metals lower in the series from their compounds during chemical reactions. For instance, magnesium (higher in the series) can displace zinc from zinc sulfate solution:
      [ Mg + ZnSO_4 → MgSO_4 + Zn ]

    Corrosion and Prevention:

    • Q13: How does corrosion affect metals and what are some methods to prevent it?
    • Answer: Corrosion is the gradual destruction of metals by chemical reactions with the environment, like rusting of iron in the presence of oxygen and moisture. Prevention methods include galvanization, painting, or coating metals with a protective layer to prevent exposure to corrosive elements.

    Non-metals and Acidity:

    • Q14: How do non-metals typically react with bases and what does this reveal about their nature?
    • Answer: Non-metals react with bases to form salts and water, indicating their acidic nature. For example, when chlorine gas reacts with sodium hydroxide, it forms sodium chloride and water:
      [ Cl_2 + 2NaOH → NaCl + H_2O + NaOCl ]

    Study Material on “Physical Properties of Metals and Non-metals”

    Appearance and State:

    • Q15: How do the appearances and states of metals and non-metals at room temperature differ?
    • Answer: Most metals are shiny solids (except mercury, which is a liquid) and have a high melting point, reflecting their strong metallic bonds. Non-metals can be solids, liquids, or gases with varied appearances, from the shiny graphite to the colorless and odorless noble gases, indicating the diverse intermolecular forces present.

    Conductivity and Malleability:

    • Q16: Why are metals good conductors of electricity and malleable, while non-metals are not?
    • Answer: Metals have free-moving electrons that allow them to conduct electricity and are malleable due to the layers of atoms that can slide over each other without breaking the metallic bond. Non-metals lack these free electrons and have a more rigid structure, making them poor conductors and brittle.

    Practical Applications and Exercises

    Q17: Propose a simple experiment to test the conductivity of metals and non-metals.

    • Answer: To test conductivity, create a circuit with a battery, a bulb, and two wires. Attach one wire to the battery and the bulb. Use various metal and non-metal samples to complete the circuit by connecting the second wire. If the bulb lights up, the sample is a conductor (metal). If not, it is an insulator (non-metal).

    Q18: Discuss how alloys are formed and give two examples where alloys are preferred over pure metals.

    • Answer: Alloys are formed by melting and mixing two or more metals, or a metal and a non-metal. They are preferred over pure metals when enhanced properties are needed. For example, stainless steel (alloy of iron, chromium, and nickel) is used in utensils for its rust resistance, and bronze (alloy of copper and tin) is used in statues for its hardness and aesthetic finish.

    Environmental Impact of Metal and Non-metal Use

    Q19: What are some environmental concerns associated with the mining and processing of metals?

    • Answer: The mining and processing of metals can lead to significant environmental damage, including deforestation, soil erosion, water pollution from acid mine drainage, and air pollution from the release of sulfur dioxide and other harmful gases. The disposal of metal-containing waste can also lead to the contamination of land and water resources.

    Q20: How can the negative environmental impacts of metal extraction and use be mitigated?

    • Answer: To mitigate environmental impacts, it is crucial to implement more sustainable mining practices, such as reducing the surface footprint of mines, treating waste water, and rehabilitating mining sites after closure. Additionally, recycling metals can greatly reduce the need for new mining and the associated environmental impacts.

    Health and Safety in Handling Metals and Non-metals

    Q21: What precautions should be taken when handling metals and non-metals in the lab?

    • Answer: Safety precautions in the lab include wearing protective gear like gloves and goggles, working in a well-ventilated area, handling chemicals with care to prevent spills or reactions, and properly disposing of chemical waste. It’s also important to be familiar with the Material Safety Data Sheets (MSDS) for substances being used.

    Q22: Describe the proper disposal methods for metal and non-metal waste.

    • Answer: Metal waste can often be recycled, while non-metal waste, depending on its nature, may require special disposal methods to prevent environmental contamination. Hazardous waste should be handled according to local regulations, which may involve neutralization, encapsulation, or incineration under controlled conditions.

    Practical Exercises and Application Questions

    Q23: Suggest a project that would illustrate the recycling process of metals.

    • Answer: A practical project could involve collecting various metal objects, such as aluminum cans or copper wires, and simulating the recycling process by sorting, cleaning, and melting down the metals to form a new product, demonstrating the steps involved in metal recovery and reuse.

    Q24: How can understanding the properties of metals and non-metals contribute to making informed decisions in everyday life?

    • Answer: Understanding these properties can help individuals make informed decisions about materials they use daily, from choosing stainless steel utensils for their rust-resistant properties to selecting appropriate materials for electrical wiring or insulation in homes.