Metals and Non-metals Worksheet For Class 8 - Free Printable

Let's solve each part of the worksheet step by step and explain the answers clearly.

---

1. Fill in the blanks

a. Helium and oxygen are ______ gases.
✔ Answer: *Inert* (or *noble*)
🔹 Explanation: Helium is a noble gas, and oxygen is not inert — but this seems like a typo. "Helium" is inert, but "organ" is not a gas. Likely meant to be "oxygen", but even then, oxygen is not inert. So, probably it should be:
➡️ Helium and argon are inert gases.
✔ Corrected answer: Inert
✔️ Noble gases like helium and argon do not react easily due to their full valence shells.

---

b. Non-metals do not react with ______.
✔ Answer: *Acids*
🔹 Explanation: Non-metals generally do not react with acids because they lack the tendency to lose electrons (unlike metals). Metals react with acids to produce hydrogen gas, but non-metals don’t.

---

c. Zn + CuSO₄ → ZnSO₄ + Cu is an example of a ______ reaction.
✔ Answer: *Displacement*
🔹 Explanation: This is a single displacement reaction, where a more reactive metal (Zn) displaces a less reactive metal (Cu) from its salt solution.

---

d. Metals can be drawn into thin wires because of their property of ______.
✔ Answer: *Ductility*
🔹 Explanation: Ductility is the ability of a material to deform under tensile stress, allowing metals to be pulled into wires.

---

2. Complete these reactions

a. Iron (Fe) + Oxygen (O₂) + Water (H₂O) →
✔ Answer: *Iron(III) oxide-hydroxide* or *Hydrated iron(III) oxide*
More precisely:
→ Fe₂O₃·xH₂O (Rust)
🔹 Explanation: Iron rusts when exposed to oxygen and moisture. The chemical formula for rust is often written as Fe₂O₃·xH₂O (hydrated iron(III) oxide).

---

b. Sulphur (S) + Oxygen (O₂) →
✔ Answer: *Sulphur dioxide (SO₂)*
🔹 Equation:
S + O₂ → SO₂
🔹 Explanation: Sulphur burns in oxygen to form sulphur dioxide, a pungent gas.

---

c. An oxide formed in all the three reactions?
Wait — only two reactions were given above. But let’s assume it refers to the oxides formed in (a) and (b), and possibly a third implied one (e.g., metal + oxygen).

But looking at:
- (a): Iron → forms iron oxide
- (b): Sulphur → forms sulphur dioxide (non-metal oxide)

So no single oxide is common to both.

But perhaps the question means: *"What type of oxide is formed?"*

Alternatively, maybe there's a typo and it's asking about the type of oxide formed.

But based on context, likely:

✔ Answer: *Metallic and non-metallic oxides are formed.*
But since the question says “an oxide formed in all the three reactions,” and only two are listed, we may need to interpret it differently.

Wait — perhaps the third reaction is implied: e.g., Magnesium + Oxygen → Magnesium oxide

Then:
- Fe → Fe₂O₃ (metal oxide)
- S → SO₂ (non-metal oxide)
- Mg → MgO (metal oxide)

So no common oxide.

But if the question is asking what kind of oxides are formed, the answer would be:

✔ Answer: *Metal oxides and non-metal oxides are formed.*

But if it's asking for a specific oxide that appears in all, then none.

But likely, it's a mistake — perhaps it means: "What types of oxides are formed?"

Alternatively, re-read: "An oxide formed in all the three reaction?" — probably a typo.

But assuming only two reactions are provided, and perhaps the third is missing.

Given that, best possible interpretation:

✔ Answer: *No single oxide is formed in all three reactions.*
But if it's asking for a general pattern:
👉 Metals form basic oxides; non-metals form acidic oxides.

But since the question is unclear, let's assume it's asking for the common product type.

Best safe answer:

✔ Answer: *Oxides of metals and non-metals are formed.*

But perhaps the intended answer is:

👉 The formation of oxides is common in all these reactions.

So final answer:

✔ Answer: *Oxides are formed in all the reactions.*

---

3. Define

a. Corrosion
✔ Definition: *Corrosion is the gradual destruction of a metal by chemical or electrochemical reaction with its environment, such as oxygen, water, or acids.*
🔹 Example: Rusting of iron.

---

b. Reactivity series
✔ Definition: *The reactivity series is a list of metals arranged in order of decreasing reactivity. A more reactive metal can displace a less reactive metal from its compound.*
🔹 Example: Potassium > Sodium > Calcium > Magnesium > Aluminum > Zinc > Iron > Copper > Silver > Gold.

---

c. Metalloids
✔ Definition: *Metalloids are elements that have properties intermediate between metals and non-metals. They are located along the zigzag line on the periodic table.*
🔹 Examples: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po).

---

4. Give Reasons

a. Sodium metals is always kept immersed in kerosene oil.
✔ Reason: *Sodium is highly reactive and reacts violently with air and moisture. Kerosene oil prevents contact with air and water, thus preventing oxidation and explosion.*
🔹 Sodium reacts with oxygen and water vapor in air, so it must be stored in an inert medium like kerosene.

---

b. Colour of copper sulphate changes when zinc strip is dipped in it.
✔ Reason: *Zinc is more reactive than copper. It displaces copper from copper sulphate solution, forming zinc sulphate (colorless) and copper metal (reddish-brown).*
🔹 Reaction:
Zn + CuSO₄ → ZnSO₄ + Cu
🔹 Blue color of CuSO₄ fades as Cu²⁺ ions are removed, and colorless ZnSO₄ forms.

---

c. Bells are made of metals and non-metals.
⚠️ This statement is incorrect. Bells are typically made of metals only, especially alloys like bronze (copper + tin).
But if the question means "bells are made of metallic materials", then:

✔ Corrected Reason: *Bells are made of metals because metals are sonorous (produce sound when struck) and durable. Non-metals are not used in bell-making due to lack of sonority and strength.*
🔹 So, the statement is false — bells are made of metals, not non-metals.

But if the question is asking why bells are made of metals, then:

✔ Answer: *Metals are sonorous and strong, making them suitable for producing clear sounds when struck. Non-metals are not sonorous and brittle, so they are not used in bell-making.*

---

✔ Final Answers Summary:

---

#### 1. Fill in the blanks
a. Inert
b. Acids
c. Displacement
d. Ductility

---

#### 2. Complete these reactions
a. Fe + O₂ + H₂O → Fe₂O₃·xH₂O (rust)
b. S + O₂ → SO₂ (sulphur dioxide)
c. Oxides are formed in all the reactions. (or *Metal and non-metal oxides are formed*)

---

#### 3. Define
a. Corrosion: Gradual destruction of metal by reaction with environment (e.g., rusting).
b. Reactivity series: List of metals in order of decreasing reactivity.
c. Metalloids: Elements with properties between metals and non-metals.

---

#### 4. Give Reasons
a. Sodium is kept in kerosene to prevent reaction with air and moisture.
b. Color change occurs due to displacement of Cu by Zn, forming colorless ZnSO₄.
c. Bells are made of metals (not non-metals) because metals are sonorous and strong.

---

Let me know if you'd like this formatted as a printable answer sheet!