---
title: "Metallic bond versus covalent bond"
subject: "Civil Engineering Materials"
chapter: 1
key: "semester_3/civil_engineering_materials:metallic-covalent-bond"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/metallic-covalent-bond
site: BCT Engineering
---

# Metallic bond versus covalent bond

Civil Engineering Materials · Chapter 1: Introduction to Civil Engineering Material

- Asked in: 2065 Shrawan (old course), 4 marks
- Video: [Atomic Hook-Ups - Types of Chemical Bonds: Crash Course Chemistry #22](https://www.youtube.com/watch?v=QXT4OVM4vXI) — CrashCourse
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/metallic-covalent-bond
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-1

## Question

Differentiate between metallic and covalent bond.

## Short answer

A metallic bond forms by attraction between positive metal ions and a sea of delocalized electrons, is non‑directional, and results in good conductivity and ductility. A covalent bond arises from shared localized electron pairs between atoms, is directional, and yields hard, brittle materials with poor conductivity.

## Answer

| Basis | Metallic bond | Covalent bond |
|---|---|---|
| Formation | Attraction between positive metal ions and a sea of free electrons | Sharing of electron pairs between two atoms |
| Electrons | Delocalised, free to move | Localised between the bonded atoms |
| Direction | Non-directional | Directional (fixed bond angles) |
| Conductivity | Good electrical and thermal conductor | Generally poor conductor |
| Mechanical nature | Ductile and malleable | Hard and brittle |
| Melting point | Moderate to high | Very high (diamond) or low (molecular solids) |
| Lustre | Metallic lustre | Usually none |
| Examples | Iron, copper, aluminium | Diamond, silica, polymers |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Metallic bonds are
   A. directional
   B. absent
   C. non-directional
   D. fixed angles
   Answer: C. Covalent is directional. (Key point: Direction)

2. Which is generally a good conductor?
   A. Covalent solid
   B. Diamond
   C. Silica
   D. Metallic solid
   Answer: D. Free electrons. (Key point: Conductivity)

3. Covalent solids are usually
   A. hard and brittle
   B. ductile and malleable
   C. soft always
   D. lustrous
   Answer: A. Contrast to metals. (Key point: Mechanical)

## Related in Civil Engineering Materials

- [Short note: metallic bond](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Ametallic-bond-short-note) — Civil Engineering Materials, chapter 1