NCERT Solutions Class 7 Science Chapter 4 - The World of Metals and Non-Metals

Metals and nonmetals are the building blocks of the modern world. Iron and steel are the foundation of tall skyscrapers; oxygen is vital for life; carbon is in our pencils. NCERT Solutions Chapter 4 of the Class 7 Science class acts as the bridge to the existing knowledge on the properties, behaviour, and uses of metals and nonmetals; it introduces students to core chemistry ideas.

For example, it explained that metals are usually hard, shiny, and good conductors, while nonmetals are likely dull, brittle, and insulators. It also described how metals and nonmetals react with air, water, acids, and bases, and enabled students to see and experiment and learn chemistry rather than simply read or listen.

1.0NCERT Solutions Class 7 Science Chapter 4 - The world of metals and non-metals – Download PDF

Download the free PDF of NCERT Solutions for Class 7 Science Chapter 4 from below:

2.0Key Concepts in Chapter 4 – The World of metals and non-metals

Chapter Overview: Metals and Nonmetals 

Metals and nonmetals can be categorized based on their physical and chemical properties. This chapter discusses:

• What is metal and nonmetal?  
• How can they be distinguished based on appearance, hardness, malleability and conductivity? 
• How do they react with air, water and acids? 
• How do we use them in everyday life?

These concepts are discussed with examples and simple experiments to foster an understanding of these concepts, while also helping students to visualize and make connections with the theory and the world outside.

Physical properties of metals and nonmetals 

• Metals are usually shiny (lustrous), hardness, malleable (can be made into sheets), ductile (can be made into wire), sonorous (ringing sound), good conductors of heat and electricity.
• Nonmetals usually dull, brittle and poor conductors (with graphite being a notable exception) 

Chemical properties 

• Reaction with oxygen: metals form basic oxides, nonmetals form acidic oxides. 
• Reaction with water - some metals (sodium) react vigorously with water. 
• Reaction with acids - metals usually form hydrogen gas when they react with acids! 
• Nonmetals usually do not undergo a reaction with dilute acids! 

Displacement reactions 

• More reactive metals can displace less reactive metals from the compounds.- this is an important consideration when assessing reactivity.

Applications in Everyday Life

• Metals such as iron, aluminum, and copper are utilized in building, transportation, and electrical wire.
• Non-metals, such as oxygen, nitrogen, sulfur, and chlorine, are found in breathing, pesticides, antiseptics, and so forth.

Important Science and Applications

At Home

• Colloquially, metals are used as the utensils we eat with, tools we work with, wires we conduct electricity with, and coins we use to pay for things, due to their strength and conductivity.
• Medications like iodine, phosphorus, or chlorine, and products like hand sanitizers or bleach are often made from non-metals.

In Nature

• Oxygen is required for respiration.
• Nitrogen is a critical component in agriculture (fertilizers).
• Carbon is a basic element of all living organisms and fuels.

In Industry

• Metals are used extensively in manufacturing or in building structure and appliances.
• Non-metals support the processes used to manufacture plastics, explosives, or water-purifying chemicals.

Promoting Scientific Inquiry

This chapter promotes curiosity through asking students to explore the ‘how and why’ material behaves in everyday settings:

• Why do metal wires conduct electricity but rubber does not?
• Why does iron rust when it is left in the rain?
• Why are copper and aluminum used in wires?
• Why should we not use wood or plastic in electrical appliances?

Simple demonstrations in class often lead students to reasonable conclusions based on their observables in everyday settings.

3.0Key Features of NCERT Solutions – Chapter 4 : The World of Metals and Non-metals

1. Clarity of Concept

The author's explanations highlight differences between metals and non-metals using examples, activities, and simple language in the use of scientific terms. Likewise, students are learning not only "what," but also "why." 

2. Thorough Gradual Responses

All in-text book questions and end-of-chapter exercises are also solved with an explanation that helps students feel confident in their understanding of the material specifically for assessment in the chapter as well as in future learning. 

3. Support of Scientific Thinking

The solutions outline the importance of experimentation and logic, which is essential for developing the skills in future scientists. 

4. Real-World Connections

Examples and practical uses provide student input for relating textbook materials to their world, increasing the interest of students and taking from the text. 

5. Improved Retention 

Using tables, comparisons, and real world connections help to improve retention and understanding of the topic.