Boiling Points of the Noble Gases
Lesson notes
Overview
Heavier atoms have stronger London dispersion forces, so they boil at higher temperatures. This topic is rated beginner and is number 16 of 110 in Chemistry. Core ideas and first intuitions. No prior knowledge needed.
What you are seeing
The panel above shows a bar chart that compares values on one scale, so differences in size are easy to see. The animation is drawn live from the model, so everything you see responds to the sliders. Press Space to pause, use Restart to replay from the start, and change the speed to slow down quick events.
In depth
Noble gases exist as single atoms with only weak London dispersion forces between them, so all have very low boiling points, from −269 °C for helium to −62 °C for radon. These forces come from temporary shifts in the electron cloud and increase with the number of electrons, so heavier atoms are held together more strongly and boil at higher temperatures. The same reasoning explains the trend in boiling points of the halogens and of alkanes.
Reading the relationship
The expression "London forces ∝ electrons" is a compact summary of the idea. It uses the symbols L, o, n, d, f, r; name what each one stands for before you start. Notice that it contains a proportionality, so the two sides rise and fall together. Then use the sliders to see how changing one quantity changes the others.
A guided exploration
1. Run the animation once with the default settings and describe in words what happens. 2. Change one slider at a time and note which quantity responds most. 3. Push each slider to its extreme and decide whether the result still makes sense.
Try this
Start by only moving one slider at a time. Say aloud what you expect, then check.
Common pitfalls
Keep the particle picture in mind. Mistakes often come from treating a rate, an amount and an equilibrium position as the same thing, or from ignoring units and conditions.
How it connects
It builds on “Alkali Metal Melting Points”, the topic before it in Chemistry. Once you are comfortable, continue with “Densities of Common Metals”.
Why it matters
Chemistry links the tiny scale of atoms to the materials, medicines and energy we use every day.
Where you might use it
- Revising “Boiling Points of the Noble Gases” before a class, exam or certification
- Predicting how fast a reaction runs in a lab or an industrial plant
- Choosing materials, medicines and fuels based on how their atoms bond and react
- Reading the labels and data sheets of cleaning products, batteries and food
Frequently asked questions
What is Boiling Points of the Noble Gases?
Heavier atoms have stronger London dispersion forces, so they boil at higher temperatures. It is a beginner topic in Chemistry.
How do I use the Boiling Points of the Noble Gases simulation?
The panel at the top shows a bar chart that compares values on one scale, so differences in size are easy to see. Move the sliders one at a time, then press Space to pause the animation and look closer.
What does the formula mean?
The expression London forces ∝ electrons packs the idea into symbols. Name each symbol first, then change one quantity with the sliders and see which others respond.
Who is this topic for?
Core ideas and first intuitions. No prior knowledge needed. If the quiz feels hard, reread the lesson notes and try the previous topic first.
What should I learn before this?
Start with “Alkali Metal Melting Points”, the previous topic in Chemistry. Each topic in a subject builds on the ones before it.
How do I track my progress?
Press “Mark as learned” on this page. Progress is stored only in this browser and is never sent anywhere. The Browse page can show topics you have learned or still need to learn.
Quick quiz
More in Chemistry
See all →Densities of Common Metals
From lightweight lithium to dense gold: density depends on atomic mass and packing.
Ionic Bonding
When the electronegativity gap is large, one atom takes an electron and opposite charges attract.
Covalent Bonding
Atoms share electron pairs. Equal sharing between identical atoms gives a nonpolar bond.