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