Mnemonics: The World of Metals and Non-metals | Science (Curiosity) Class 7 - New NCERT PDF Download

1. Properties of Metals 

Mnemonic: Hi, do cows like Sheep?

• Hi - Hard
• Do – Ductile
• Cow – Conductors (good) of heat and electricity
• Like – Lustrous
• Sheep – Sonorous: Can make ringing sounds 

Mnemonic Explanation: This sentence helps recall the key characteristics of metals: they are shiny, hard, ductile, conduct heat and electricity, have metallic lustre, and are sonorous.

2.  Distinguishing Properties of Metals and Non-Metals

(i) Malleability vs Brittleness 

Mnemonic: Metal Bends, Non-metal Breaks

• Metal → Bends into sheets (Malleable)
• Non-metal → Breaks into pieces (Brittle)

Mnemonic Explanation: This short phrase distinguishes how metals and non-metals behave when hammered. Metals are malleable; non-metals are brittle.

(ii) Sonority

Mnemonic: Metal Bells Sing, Wood Just Thuds

• Metal Bells Sing → Metals are sonorous
• Wood Just Thuds → Non-metals are not sonorous

Mnemonic Explanation: Highlights how metals ring when struck, while non-metals don’t.

(iii) Heat Conduction

Mnemonic: Metal Spoon Burns, Wooden Spoon Can't

• Metal Spoon Burns – Good conductor of heat
• Wooden Spoon Can't– Poor conductor (remains cool)

Mnemonic Explanation: Helps remember that metals conduct heat, non-metals like wood do not.

(iv) Acidic or Basic Oxides

Mnemonic: Metal Base, Non-metal Acid – MBA
Easy recall because “MBA” is a popular degree → memory anchor.

• Metal → Base (e.g., Magnesium oxide is basic)
• Non-metal → Acid (e.g., Sulfur dioxide forms acid)

Mnemonic Explanation: Helps identify the nature of oxides based on whether they come from metals or non-metals.

3. Rusting Conditions: 

Mnemonic: "RAW → Rust needs Air + Water."
Mnemonic Explanation: This mnemonic simplifies the conditions required for rusting:

• R = Rust: Rusting specifically occurs in iron and steel, forming reddish-brown flakes.
• A = Air (Oxygen): Oxygen from the air is essential for the rusting reaction.
• W = Water (Moisture): Water provides the medium for oxygen to react with iron.

It reminds us that rusting requires both air and water (moist air), and iron won’t rust in dry air or water alone.

4.  Preventing Rust: Galvanisation

Mnemonic: Paint Oil Zinc (POZ)
Mnemonic Explanation: This mnemonic covers methods to prevent iron from rusting:

• Paint: Painting iron surfaces creates a barrier against air and moisture.
• Oil: Applying oil or grease forms a protective layer to block moisture and air.
• Zinc: Galvanisation involves coating iron with zinc to prevent rusting.

This concise mnemonic helps recall practical ways to protect iron objects like tools or bridges.

5. Uses of Non-Metal

Mnemonic: ONCIC

Mnemonic Explanation: With these, you can relate the first letter of each non-metal with the same letter function.

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