Explanation

• The chemical name of chalk is Calcium carbonate.
• Its chemical formula is CaCO₃.
• It is a soft, white mineral.
• Commonly used in blackboard chalk and limestone.
• Found naturally in rocks and marine shells.

Last verified on 30-04-2026

Explanation

Bismuth is the only pure metal that expands when it solidifies (freezes).

Most substances contract on solidification, but bismuth behaves unusually—its solid form occupies a slightly larger volume than its liquid form.

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Explanation

• The cheapest source of electricity generation is Solar Energy.
• Solar energy uses sunlight, which is free and renewable.
• Costs have dropped significantly due to modern solar panel technology.
• It avoids fuel costs and environmental pollution.

Last verified on 31-03-2026

Explanation

• Diamond is a naturally occurring allotropic form of carbon.
  • Allotropy means a single element can exist in more than one form with different structures and properties.
  • It is extremely hard.
  • It has a high melting point.
  • It is widely used in jewelry and cutting tools.

Additional information:

• Graphite – soft, good conductor
• Fullerenes (C60) – spherical molecules
• Carbon nanotubes – tubular, high strength
• Amorphous carbon – coal, soot
• Lonsdaleite – hexagonal diamond

Last verified on 17-01-2026

Explanation

• Copper is a chemical element with the symbol Cu and atomic number 29. 
• It is a soft, malleable, and ductile metal with a reddish-orange color.

The some major elements with their symbols:

• Hydrogen - H
• Sodium - Na
• Carbon - C
• Nitrogen - N
• Oxygen - O
• Fluorine - F
• Chlorine - Cl
• Potassium - K
• Helium - He
• Neon - Ne
• Calcium - Ca
• Sulphur - S
• Phosphorus - P
• Aluminium - Al
• Magnesium - Mg
• Iron - Fe

Last verified on 16-03-2026