# Metals - Grade 10 (SEE) Science
## Complete Chapter Notes with All Exercises - NEB Curriculum
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## 🎯 Chapter Overview
**From the iron in our buildings to the gold in our jewelry and the copper in our wires, metals are the backbone of our modern world.** This chapter, "Metals," dives into the fascinating properties, occurrence, and uses of some of the most important metallic elements. These notes are designed to be your complete guide, making it easy to master the concepts.
**This is a core chapter in chemistry with significant weightage in the SEE exam.** We will cover the fundamental differences between minerals and ores, explore the reactivity of metals, and take a deep dive into the properties and uses of Iron, Aluminium, Copper, Silver, and Gold. Every question from your textbook, including definitions, give reasons, and differentiations, is solved here with clear, step-by-step explanations.
**Weightage:** 7-9 marks in SEE examination
**Time Required:** 15-20 periods
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## 📚 Learning Objectives
After studying this chapter, you will be able to:
- Differentiate between minerals and ores.
- Understand why metals occur in free (native) or combined states.
- Describe the physical properties of key metals like Iron, Aluminium, and Copper.
- Write the electronic configuration and identify the position of these metals in the periodic table.
- List the main ores of Iron, Aluminium, Copper, Silver, and Gold.
- Explain the various uses of these metals by linking them to their properties.
- Arrange metals in order of their reactivity.
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## 💎 1. Metallurgy Basics: Minerals, Ores & Reactivity

### Minerals vs. Ores
This is a fundamental concept in metallurgy (the science of metals).
**Analogy:** Think of plants in a garden. All apple trees are plants, but not all plants are apple trees. Similarly...
**All ores are minerals, but not all minerals are ores.**

| Feature | Minerals | Ores |
|---|---|---|
| **Definition** | Naturally occurring, pure inorganic substances, usually in a crystalline form. | Minerals from which metals can be extracted **profitably and conveniently**. |
| **Metal Content**| May contain a low percentage of metal. | Contain a high percentage of metal. |
| **Extraction** | It is not always profitable to extract metal from all minerals. | It is always profitable to extract metal from ores. |
| **Example**| Clay ($Al_2O_3 \cdot 2SiO_2 \cdot 2H_2O$) is a mineral of aluminium. | Bauxite ($Al_2O_3 \cdot 2H_2O$) is the main **ore** of aluminium. |

### Occurrence of Metals
- **Free/Native State:** Less reactive metals do not easily react with air, water, or other chemicals. They are found in their pure, elemental form in nature.
  - **Examples:** Gold (Au), Silver (Ag), Platinum (Pt).
- **Combined State:** Most metals are reactive and are found in nature combined with other elements, forming compounds like oxides, sulphides, and carbonates. These compounds are the minerals and ores.
  - **Examples:** Iron (Fe), Aluminium (Al), Copper (Cu), Zinc (Zn).

### The Reactivity Series of Metals 👑
This is a "power ranking" of metals from most reactive to least reactive. It's super important for understanding their properties.

| Metal | Symbol | Reactivity | Mnemonic |
|---|---|---|---|
| Potassium | K | **Most Reactive** | **P**lease |
| Sodium | Na | | **S**top |
| Calcium | Ca | | **C**alling |
| Magnesium | Mg | | **M**e |
| Aluminium | Al | | **A** |
| Zinc | Zn | | **Z**ebra |
| Iron | Fe | | **I** |
| Lead | Pb | | **L**ike |
| Hydrogen | (H) | (Reference) | **H**er |
| Copper | Cu | | **C**all |
| Mercury | Hg | | **S**mart |
| Silver | Ag | | **G**oat |
| Gold | Au | **Least Reactive** | |

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## 🔬 2. A Detailed Look at Important Metals

### A. Iron (Fe)
- **Introduction:** The most widely used metal, known for its strength.
- **Symbol:** Fe | **Atomic No:** 26 | **Atomic Mass:** 56 | **Valency:** 2 (ferrous), 3 (ferric)
- **Position & E-Configuration:**
  - **Period:** 4, **Group:** 8 (VIII)
  - **Sub-shell:** $1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^6$
- **Ores:** **Haematite ($Fe_2O_3$)**, Magnetite ($Fe_3O_4$), Iron Pyrite ($FeS_2$).
- **Physical Properties:**
  - Silvery-grey, lustrous metal.
  - Malleable and ductile.
  - Good conductor of heat and electricity.
  - High density and high melting point.
- **Uses:**
  1.  Used to manufacture **steel**, a vital alloy.
  2.  Used in construction (rods, beams, bridges).
  3.  Used for making machinery, tools, and vehicles.
  4.  Used to make magnets.

### B. Aluminium (Al)
- **Introduction:** A remarkably light and corrosion-resistant metal.
- **Symbol:** Al | **Atomic No:** 13 | **Atomic Mass:** 27 | **Valency:** 3
- **Position & E-Configuration:**
  - **Period:** 3, **Group:** 13 (IIIA)
  - **Sub-shell:** $1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^1$
- **Ores:** **Bauxite ($Al_2O_3 \cdot 2H_2O$)**, Cryolite ($Na_3AlF_6$), Kaolin (China clay).
- **Physical Properties:**
  - Silvery-white, lightweight metal.
  - Malleable and ductile.
  - Excellent conductor of heat and electricity.
  - Highly resistant to corrosion due to a protective oxide layer.
- **Uses:**
  1.  Used to make aeroplane and automobile parts because it's light and strong.
  2.  Used for making cooking utensils.
  3.  Used for making **aluminium foil** for wrapping food.
  4.  Used in electrical cables as a cheaper alternative to copper.

### C. Copper (Cu)
- **Introduction:** One of the first metals used by humans, essential for electrical wiring.
- **Symbol:** Cu | **Atomic No:** 29 | **Atomic Mass:** 64 | **Valency:** 1 (cuprous), 2 (cupric)
- **Position & E-Configuration:**
  - **Period:** 4, **Group:** 11 (IB) - A **Coinage Metal**.
  - **Sub-shell:** $1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^1 \ 3d^{10}$ (Note: exceptional configuration for stability)
- **Ores:** **Copper Pyrite ($CuFeS_2$)**, Chalcocite/Copper Glance ($Cu_2S$), Cuprite ($Cu_2O$).
- **Physical Properties:**
  - Reddish-brown metal with a bright lustre.
  - Highly malleable and ductile.
  - Excellent conductor of electricity (second only to silver).
- **Uses:**
  1.  Used extensively for making **electrical wires and cables**.
  2.  Used for making water pipes and heating utensils.
  3.  Used for making coins and statues.
  4.  Used in electroplating.

### D. Silver (Ag)
- **Introduction:** A precious metal known for its brilliant lustre and conductivity.
- **Symbol:** Ag | **Atomic No:** 47 | **Atomic Mass:** 108 | **Valency:** 1
- **Position & E-Configuration:**
  - **Period:** 5, **Group:** 11 (IB) - A **Coinage Metal**.
  - **Sub-shell:** [Kr] $5s^1 \ 4d^{10}$
- **Ores:** **Argentite/Silver Glance ($Ag_2S$)**. Also found in a native state.
- **Uses:**
  1.  Used for making jewellery and decorative items.
  2.  Used for making high-quality mirrors.
  3.  Used in dentistry for fillings.
  4.  Silver salts are used in photography.

### E. Gold (Au)
- **Introduction:** The most prized precious metal, known for its beauty and unreactivity. The "King of Metals".
- **Symbol:** Au | **Atomic No:** 79 | **Atomic Mass:** 197 | **Valency:** 1 (aurous), 3 (auric)
- **Position & E-Configuration:**
  - **Period:** 6, **Group:** 11 (IB) - A **Coinage Metal**.
  - **Sub-shell:** [Xe] $6s^1 \ 4f^{14} \ 5d^{10}$
- **Ores:** Mostly found in **native state** (free gold) in alluvial sand and quartz veins.
- **Uses:**
  1.  Used for making valuable **jewellery and ornaments**.
  2.  Used for making coins and medals.
  3.  Used in dentistry for making crowns.
  4.  Used for electroplating other metals to give a golden finish.
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## 📋 3. COMPLETE EXERCISE SOLUTIONS

### **1. Differentiate Between:**
**a. Minerals and Ores**
| Minerals | Ores |
|---|---|
| Naturally occurring inorganic substances from which metals can be extracted. | Minerals from which metals can be extracted **profitably and conveniently**. |
| All minerals are not ores. | All ores are minerals. |
| Example: Clay is a mineral of aluminium. | Example: Bauxite is the chief ore of aluminium. |

### **2. Give Reasons:**
**a. Iron is not found in a free state in nature.**
**Answer:** Iron is a reactive metal. It readily reacts with oxygen and moisture in the atmosphere to form compounds like iron oxide (rust). Due to this high reactivity, it is found in a combined state as ores, not in a free state.

**b. Parts of an aeroplane are made of aluminium but not iron.**
**Answer:** Because aluminium is a **lightweight yet strong metal**, which is crucial for flight. Additionally, it is **rust-free** as it forms a protective layer of aluminium oxide, making it more durable than iron which rusts easily.

**c. Gold and Silver are found in a native (free) state.**
**Answer:** Gold and silver are very low in the reactivity series. They are unreactive and do not react with air, water, or other common chemicals under normal conditions. This stability allows them to exist in their pure, metallic form in nature.

**d. Food is wrapped in aluminium foil.**
**Answer:** Although aluminium is a reactive metal, it instantly reacts with oxygen in the air to form a very thin, tough, and non-reactive protective layer of aluminium oxide ($Al_2O_3$). This layer prevents the metal from reacting with the food and also acts as a barrier to moisture and air, keeping the food fresh.

**e. Gold is called the 'king of metals'.**
**Answer:** Gold is extremely unreactive. It does not tarnish or react with air, water, acids, or alkalis. This exceptional resistance to corrosion and its lasting beauty and lustre earn it the title 'king of metals'.

### **3. Answer the following questions:**
**a. List two main ores for the following metals:**
- **Iron:** Haematite ($Fe_2O_3$), Magnetite ($Fe_3O_4$)
- **Aluminium:** Bauxite ($Al_2O_3 \cdot 2H_2O$), Kaolin (China Clay)
- **Copper:** Copper Pyrite ($CuFeS_2$), Chalcocite ($Cu_2S$)
- **Silver:** Argentite ($Ag_2S$), also found as native silver.

**b. Why are gold and silver used for making jewellery?**
**Answer:** Gold and silver are used for making jewellery for three main reasons:
1.  **Lustre:** They have a bright, attractive shine.
2.  **Unreactivity:** They do not rust or tarnish, so their beauty lasts.
3.  **Malleability & Ductility:** They are very soft and can be easily beaten into thin sheets and drawn into intricate wires to create beautiful designs.

**c. Arrange the following metals in ascending order of reactivity: Gold, Iron, Aluminium, Silver, Copper.**
**Answer:** Ascending order (from least reactive to most reactive) is:
**Gold < Silver < Copper < Iron < Aluminium**
*(This order is based on the reactivity series.)*

**d. Briefly write about the occurrence of metals in Nepal.**
**Answer:** Nepal has deposits of several minerals. Iron ore is found in areas like Phulchowki (Lalitpur), Tanahun, and Chitwan. Copper deposits are known to exist in various parts of the country. Gold is found in its native state in the sands of rivers like the Rapti, Sunkoshi, and Kaligandaki.

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## ✅ 4. CHAPTER CHECKLIST & EXAM TIPS
**Exam Hotspots 🔥:**
-   **Ores:** Memorizing the main ore of each metal (Haematite, Bauxite, Copper Pyrite) is a must.
-   **Uses:** Be ready to list at least two uses for each metal. Questions often ask why a metal is suitable for a specific use (e.g., Aluminium in planes).
-   **Give Reasons:** Questions on reactivity (why Gold is free, why Iron is not) are extremely common.
-   **Reactivity Series:** Understanding this series helps answer many "Give Reason" questions.

**Your Pre-Exam Checklist:**
- [ ] I can differentiate between a mineral and an ore with an example.
- [ ] I can name the main ore of Iron, Aluminium, and Copper.
- [ ] I can explain why Gold is found in a native state.
- [ ] I can explain why aeroplanes are made of aluminium.
- [ ] I can list two important uses for each of the five metals studied.
- [ ] I can write the electronic configuration of Iron and Aluminium.
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## 🎊 CONCLUSION
Metals are fundamental building blocks of civilization, each with a unique personality defined by its properties. Understanding them—from their atomic structure to their large-scale applications—is key to understanding chemistry. This chapter provides a solid foundation, not just for your exams, but for appreciating the material world around you.
**Key to Success:** Link Properties to Uses + Master the Reactivity Series + Practice the 'Give Reasons' = Top Marks!