SC8 Q2W4D3: Differentiate compounds and molecules, and classify compounds

🎯 Learning Goals

At the end of the lesson, the learners will be able to:

1. Identify at least 5 examples each of metals, nonmetals, and metalloids from the periodic table with 80% accuracy.
2. Differentiate metals, nonmetals, and metalloids based on at least 3 observable properties (e.g., conductivity, luster, malleability).
3. Classify unknown elements into metals, nonmetals, or metalloids through a property-based activity with at least 80% accuracy.

🧩 Key Ideas & Terms

• Metal - element that is shiny, malleable, ductile, and a good conductor of heat and electricity
• Nonmetal - element that is brittle, dull, poor conductor of heat and electricity
• Metalloid - element with properties of both metals and nonmetals, depending on conditions
• Conductivity - ability of a substance to transfer heat or electricity
• Malleability - ability to be hammered or shaped without breaking

🔄 Prior Knowledge

Activity: Properties Brainstorm

Present learners with common materials: aluminum foil, pencil lead (graphite), and a silicon chip image. Ask: What differences do you notice in their appearance, texture, and uses?

Guide Questions:

1. Which item is shiny and conducts electricity well?
2. Which one is dull and brittle but used in writing?
3. Which one is used in electronics and shows both metallic and nonmetallic properties?

Show Answer

1. Aluminum foil → Metal
2. Graphite (pencil lead) → Nonmetal (form of carbon)
3. Silicon chip → Metalloid (semiconductor properties)

📖 Explore the Lesson (Day 3 – Metals, Nonmetals, and Metalloids)

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⚡ 1. Introduction: Why Classify Elements?

The Periodic Table of Elements is like a map of all known building blocks of matter. But instead of just listing them, scientists group them by properties. The most important broad classification is into metals, nonmetals, and metalloids. This classification helps us predict how elements behave in reactions, identify useful materials for technology, and understand trends across the periodic table.

Guiding Question: Why do you think knowing whether an element is a metal, nonmetal, or metalloid is important for engineers, doctors, and chemists?

Show Answer

Because it determines how the material can be used—whether as a conductor in wires, a nonmetal in fuels and fertilizers, or a metalloid in computer chips.

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🔹 2. Metals: The Shiny Workhorses

Metals make up about 75% of the periodic table. They dominate the left and center of the table.

• Luster: shiny surface when polished (e.g., gold jewelry, silver coins).
• Conductivity: excellent conductors of heat and electricity (e.g., copper wires).
• Malleability: can be hammered into thin sheets (e.g., aluminum foil).
• Ductility: can be drawn into wires (e.g., steel wires).
• High melting and boiling points: most are solid at room temperature (except mercury).

Examples: Iron (Fe), Aluminum (Al), Copper (Cu), Gold (Au), Silver (Ag).

Checkpoint: Why do you think metals are used for cooking pots and pans?

Show Answer

Because they are good conductors of heat, allowing food to cook evenly.

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🔹 3. Nonmetals: The Essential Contrasts

Nonmetals occupy the upper-right portion of the periodic table.

• Appearance: dull (not shiny).
• Conductivity: poor conductors (insulators).
• Brittleness: break easily if solid.
• State: many are gases at room temperature (O₂, N₂), some are solids (sulfur, phosphorus).
• Lower density and melting points compared to metals.

Examples: Oxygen (O₂), Nitrogen (N₂), Carbon (C), Sulfur (S).

Guiding Question: Why are nonmetals essential for life even though they are poor conductors and brittle?

Show Answer

Because they form the basis of biological molecules (DNA, proteins, carbohydrates) and are part of cycles that sustain life (oxygen, nitrogen, carbon cycles).

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🔹 4. Metalloids: The In-Between Elements

Metalloids are elements that show both metallic and nonmetallic properties depending on conditions.

• Can be shiny like metals but brittle like nonmetals.
• Some can conduct electricity under certain conditions (semiconductors).
• Found along the stair-step line on the periodic table.

Examples: Silicon (Si), Boron (B), Arsenic (As), Antimony (Sb).

Checkpoint: Why are metalloids like silicon so important in the electronics industry?

Show Answer

Because they can act as semiconductors, conducting electricity under certain conditions, making them perfect for controlling electric currents in computers and phones.

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🔹 5. Comparison Table

Property	Metals	Nonmetals	Metalloids
Appearance	Shiny, lustrous	Dull	Can be shiny or dull
Conductivity	Good conductors	Poor conductors	Semi-conductors
Malleability	Malleable, ductile	Brittle	Can be brittle
State (room temp)	Mostly solid	Solid, liquid, or gas	Mostly solid
Examples	Fe, Al, Cu, Au	O₂, N₂, C, S	Si, B, As, Sb

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🔹 6. Activity: Mystery Element Classification

Learners are given clues about an element’s properties. They decide if it’s a metal, nonmetal, or metalloid.

1. Shiny, malleable, conducts electricity well → ?
2. Brittle, gas at room temperature → ?
3. Shiny but brittle, semi-conductor → ?

Show Answer

1. Metal
2. Nonmetal
3. Metalloid

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🔹 7. Real-World Applications

• Metals: used in construction, transportation, technology (steel bridges, aluminum cans, copper wiring).
• Nonmetals: oxygen for breathing, nitrogen in fertilizers, carbon in fuels and biology.
• Metalloids: silicon in electronics, boron in glass, arsenic in semiconductors.

Critical Thinking: Imagine a world without silicon. What technologies would disappear or change?

Show Answer

Computers, smartphones, and most modern electronics would not exist, as silicon is the foundation of semiconductors.

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🔹 8. Extended Mini-Investigation

Activity: Periodic Table Detectives

1. Pick one metal, one nonmetal, and one metalloid.
2. Write their symbols, atomic numbers, properties, and one real-life use.
3. Share findings with the class.

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🔹 9. Reflection Prompt

Think about the three categories. Which one has the greatest impact on your daily life? Defend your answer with at least 2 examples.

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📚 References

• Zumdahl, S. S., Zumdahl, S. A., & DeCoste, D. (2018). Chemistry (10th Ed.). Cengage Learning.
• Silberberg, M. (2013). Chemistry: The Molecular Nature of Matter and Change. McGraw-Hill Education.
• Madriaga, E. (2015). Science Links: Worktext for Scientific and Technological Literacy. Rex Book Store Inc.
• Helmenstine, A. M. (2020). Introduction to the properties of metals, nonmetals, and metalloids. ThoughtCo.

💡 Example in Action (5 worked examples + 5 mini-tasks)

✨ Example 1: Copper (Cu)

Properties: Shiny, malleable, ductile, excellent conductor of electricity.
Classification: Metal.

Now You Try 1: Classify Iron (Fe) based on its properties.

Show Answer

Iron is a metal, used in steel and construction.

✨ Example 2: Oxygen (O₂)

Properties: Gas at room temperature, colorless, poor conductor.
Classification: Nonmetal.

Now You Try 2: Classify Nitrogen (N₂).

Show Answer

Nitrogen is a nonmetal, also a gas and the most abundant in the atmosphere.

✨ Example 3: Silicon (Si)

Properties: Shiny like a metal but brittle, semi-conductor of electricity.
Classification: Metalloid.

Now You Try 3: Classify Boron (B).

Show Answer

Boron is a metalloid, used in glass and detergents.

✨ Example 4: Sulfur (S)

Properties: Dull yellow solid, brittle, poor conductor.
Classification: Nonmetal.

Now You Try 4: Classify Phosphorus (P).

Show Answer

Phosphorus is a nonmetal, important in DNA and fertilizers.

✨ Example 5: Aluminum (Al)

Properties: Shiny, lightweight, malleable, excellent conductor.
Classification: Metal.

Now You Try 5: Classify Arsenic (As).

Show Answer

Arsenic is a metalloid, with mixed properties and used in semiconductors (though toxic).

📝 Try It Out (5 items)

Directions: Classify each element as a Metal, Nonmetal, or Metalloid.

1. Gold (Au)
2. Carbon (C)
3. Silicon (Si)
4. Sulfur (S)
5. Aluminum (Al)

Show Answer

1. Gold → Metal
2. Carbon → Nonmetal
3. Silicon → Metalloid
4. Sulfur → Nonmetal
5. Aluminum → Metal

✅ Check Yourself (10-item Mixed Quiz)

Directions: Answer the following questions.

🔹 Part A. Multiple Choice (1–4)

1. Which property is true only for metals?
   a. Poor conductor of heat   b. Dull appearance   c. Malleable and ductile   d. Brittle when hammered
2. Which of the following is a metalloid?
   a. Carbon (C)   b. Silicon (Si)   c. Oxygen (O₂)   d. Aluminum (Al)
3. Which nonmetal is essential for respiration?
   a. Nitrogen (N₂)   b. Oxygen (O₂)   c. Carbon (C)   d. Sulfur (S)
4. Which group of elements can behave as semiconductors?
   a. Metals   b. Nonmetals   c. Metalloids   d. Noble gases

🔹 Part B. True or False (5–7)

5. All metals are solids at room temperature except mercury.
6. Nonmetals are always shiny and conductive.
7. Metalloids show both metallic and nonmetallic properties.

🔹 Part C. Short Answer (8–10)

8. Give one example of a metal and explain its use.
9. Name one nonmetal that is important for life and explain why.
10. Explain why silicon is classified as a metalloid.

Show Answer Key

Part A
1. c – Malleable and ductile
2. b – Silicon (Si)
3. b – Oxygen (O₂)
4. c – Metalloids

Part B
5. True
6. False (nonmetals are dull and poor conductors)
7. True

Part C (Sample Answers)
8. Copper – used in electrical wiring because it is a good conductor.
9. Carbon – forms the backbone of organic molecules like DNA.
10. Because silicon is shiny like a metal but brittle, and it acts as a semiconductor in electronics.

🚀 Go Further (Day 3 – Metals, Nonmetals, and Metalloids)

Directions: Choose at least one activity to complete.

1. Periodic Table Artist 🎨
   Create a color-coded periodic table highlighting metals, nonmetals, and metalloids in different colors. Write one key property for each category.
   Example

   Metals = blue, Nonmetals = green, Metalloids = orange.
2. Everyday Materials Hunt 🏠
   List 5 items at home and identify whether the main material is a metal, nonmetal, or metalloid.
   Example

   Spoon → Metal (stainless steel); Window → Nonmetal (glass, silicon dioxide); Computer chip → Metalloid (silicon).
3. Properties Experiment (Safe Demo) 🧪
   Compare aluminum foil (metal), pencil lead (carbon, nonmetal), and silicon chip image (metalloid). Record differences in luster, flexibility, and conductivity.
   Observation

   Aluminum = shiny, malleable, conducts. Carbon = dull, brittle, poor conductor. Silicon = shiny but brittle, semi-conductor.
4. Life Without It ✍️
   Write a short paragraph: “What would life be like without nonmetals like oxygen and carbon?”
   Sample Idea

   Life would not exist, because oxygen is essential for respiration and carbon is the basis of organic molecules.
5. Tech Explorer 💻
   Research one metalloid used in modern technology. State its symbol, one property, and one real-world application.
   Example

   Silicon (Si) – brittle, semi-conductor – used in computer chips and solar panels.

🔗 My Reflection

✅ Reflection Checklist

Put a ✔️ mark for the items you agree with:

• I can name at least 3 examples each of metals, nonmetals, and metalloids.
• I can describe the difference in properties among the three groups.
• I can explain why silicon and boron are classified as metalloids.
• I can connect the properties of metals to their uses in construction and technology.
• I can explain why nonmetals are essential for life.

🔢 3-2-1 Reflection Task

Answer in your notebook:

• 3 Things I Learned: _______________________________
• 2 Questions I Still Have: _______________________________
• 1 Insight I Gained: _______________________________