- 2070 Chaitra (old course) · 4 marks
Short note: chemical bond
Short answer
Chemical bonds are forces holding atoms together. Primary bonds: ionic (electron transfer, hard/brittle), covalent (electron sharing, strong/directional), metallic (electron sea, ductile/conductive). Secondary van der Waals and hydrogen bonds are weak. Bond type determines properties like strength, conductivity, and melting point.
Write a short note on chemical bond.
A chemical bond is the force of attraction that holds atoms or ions together in a molecule or solid. Atoms bond to attain a stable (octet) electron configuration with lower energy. The type of bond decides the strength, melting point, ductility and conductivity of a material.
Primary (strong) bonds
- Ionic bond: transfer of electrons from a metal to a non-metal, giving oppositely charged ions that attract each other (NaCl, MgO). Hard, brittle, high melting point, poor conductors in solid state.
- Covalent bond: atoms share pairs of electrons (diamond, silica, polymers). Very hard and strong, directional, poor conductors.
- Metallic bond: positive ions in a sea of free electrons (iron, copper). Ductile, malleable, good conductors.
Secondary (weak) bonds
- Van der Waals and hydrogen bonds between molecules. They are weak, found in polymers, bitumen, water and ice.
| Bond | Strength | Example material |
|---|---|---|
| Ionic | Strong | Ceramics, cement minerals |
| Covalent | Very strong | Silicates, diamond |
| Metallic | Moderate to strong | Steel, aluminium |
| Van der Waals | Weak | Plastics, bitumen |
✓ Answer checked by Claude Opus 5.5 (high effort)