# Simple molecule

A small group of atoms joined by covalent bonds. The forces between molecules are weak, so these substances melt and boil easily.

Chemistry (school) · Part 03: Bonding and structure · Card 6 of 9 · Last updated 2026-10-19

## Analogy

Molecules are like a crowd of friends holding hands in small groups. The groups are easy to pull apart.

## In practice

Water, carbon dioxide and methane are simple molecules. They do not conduct electricity.

## Practice

### Flashcards

- **Why do simple molecules have low melting points?** The forces between molecules are weak and need little energy to overcome.

## Questions people ask

### Why do simple molecules have low boiling points?

Boiling only needs the weak forces between molecules to be overcome, not the strong covalent bonds inside them. Little energy is needed, so the boiling point is low. This is why substances such as water, methane and oxygen are liquids or gases at or near room temperature.

### Do larger molecules have higher boiling points?

Yes. The forces between molecules get stronger as molecules get bigger. So more energy is needed to separate them. This is why in crude oil, large molecules have high boiling points and the smaller ones boil first. It explains how fractional distillation works.

## Related concepts

- [Covalent bond](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-3/chemistry-school-part-3-concept-3)
- [Giant covalent structure](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-3/chemistry-school-part-3-concept-7)

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