Ever wondered why some substances mix whilst others don't, or... Show more
SociologySign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
52
•
5 Dec 2025
•
Comprehensive A-Level Chemistry Notes on Bonding
Hannah Egan
@hannahegan_xyym
1 / 3
Bond Polarity
Electronegativity is basically how greedy an atom is for electrons in a covalent bond. Scientists measure this on the Pauling scale from 0-4, with fluorine being the greediest at 4.0.
The usual suspects for high electronegativity are F, O, N, and Cl - remember these! As you move across a period, atoms get more electronegative because they have more protons pulling on the same shell of electrons. Going down a group, electronegativity decreases because the outer electrons are further from the nucleus.
Bonding exists on a spectrum rather than rigid categories. Pure covalent bonds (like F₂) have identical electronegativity, whilst polar covalent bonds form when the electronegativity difference is 0.3-1.7. When it's above 1.7, you get ionic bonding.
Key Tip: In polar covalent bonds like HCl, the more electronegative atom (Cl) becomes slightly negative (δ⁻) whilst the other becomes slightly positive (δ⁺). However, symmetrical molecules with identical bonds cancel out their dipoles, making them non-polar overall.
Intermolecular Forces
Van der Waals forces are the weakest intermolecular attractions, occurring between all molecules (but not ionic compounds). They happen because electrons are constantly moving around, creating temporary dipoles that influence neighbouring molecules.
More electrons mean stronger van der Waals forces, which is why larger molecules have higher boiling points. Shape matters too - molecules with greater surface area can get closer together, strengthening these forces.
Permanent dipole-dipole forces occur between polar molecules and are stronger than van der Waals. These molecules line up so their opposite charges attract, like HCl molecules arranging δ⁺ to δ⁻.
Hydrogen bonding is the strongest intermolecular force, forming when hydrogen bonds to nitrogen, oxygen, or fluorine. The huge electronegativity difference creates such strong attractions that substances like water have unusually high boiling points.
Real-world Connection: Hydrogen bonding explains why water expands when it freezes - the bonds hold molecules in a rigid structure that's less dense than liquid water, which is why ice floats!
Water's Special Properties
Here's a fascinating fact that demonstrates hydrogen bonding in action: ice floats on water because hydrogen bonds create a structured lattice in solid ice. This arrangement actually holds the water molecules further apart than in liquid water, making ice less dense.
This unique property is crucial for life on Earth - if ice sank, lakes and oceans would freeze from the bottom up, potentially killing aquatic life and dramatically altering our climate.
Exam Success: Understanding why ice floats is a classic exam question that combines electronegativity, hydrogen bonding, and density concepts - perfect for showing off your chemical knowledge!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content: Hydrogen Bonding
Most popular content in Chemistry
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Comprehensive A-Level Chemistry Notes on Bonding
Hannah Egan
@hannahegan_xyym
Ever wondered why some substances mix whilst others don't, or why water has such unusual properties? It all comes down to how atoms share electrons and the forces between molecules - concepts that'll help you ace your chemistry exams and... Show more
Bond Polarity
Electronegativity is basically how greedy an atom is for electrons in a covalent bond. Scientists measure this on the Pauling scale from 0-4, with fluorine being the greediest at 4.0.
The usual suspects for high electronegativity are F, O, N, and Cl - remember these! As you move across a period, atoms get more electronegative because they have more protons pulling on the same shell of electrons. Going down a group, electronegativity decreases because the outer electrons are further from the nucleus.
Bonding exists on a spectrum rather than rigid categories. Pure covalent bonds (like F₂) have identical electronegativity, whilst polar covalent bonds form when the electronegativity difference is 0.3-1.7. When it's above 1.7, you get ionic bonding.
Key Tip: In polar covalent bonds like HCl, the more electronegative atom (Cl) becomes slightly negative (δ⁻) whilst the other becomes slightly positive (δ⁺). However, symmetrical molecules with identical bonds cancel out their dipoles, making them non-polar overall.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Intermolecular Forces
Van der Waals forces are the weakest intermolecular attractions, occurring between all molecules (but not ionic compounds). They happen because electrons are constantly moving around, creating temporary dipoles that influence neighbouring molecules.
More electrons mean stronger van der Waals forces, which is why larger molecules have higher boiling points. Shape matters too - molecules with greater surface area can get closer together, strengthening these forces.
Permanent dipole-dipole forces occur between polar molecules and are stronger than van der Waals. These molecules line up so their opposite charges attract, like HCl molecules arranging δ⁺ to δ⁻.
Hydrogen bonding is the strongest intermolecular force, forming when hydrogen bonds to nitrogen, oxygen, or fluorine. The huge electronegativity difference creates such strong attractions that substances like water have unusually high boiling points.
Real-world Connection: Hydrogen bonding explains why water expands when it freezes - the bonds hold molecules in a rigid structure that's less dense than liquid water, which is why ice floats!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Water's Special Properties
Here's a fascinating fact that demonstrates hydrogen bonding in action: ice floats on water because hydrogen bonds create a structured lattice in solid ice. This arrangement actually holds the water molecules further apart than in liquid water, making ice less dense.
This unique property is crucial for life on Earth - if ice sank, lakes and oceans would freeze from the bottom up, potentially killing aquatic life and dramatically altering our climate.
Exam Success: Understanding why ice floats is a classic exam question that combines electronegativity, hydrogen bonding, and density concepts - perfect for showing off your chemical knowledge!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Mock Exam
Quiz
Flashcards
Essay
Similar content
Understanding Polar Molecules
Explore the concepts of polar and non-polar molecules, including the role of electronegativity and molecular symmetry. This summary covers key definitions, examples like water, and the significance of bond types based on electronegativity differences. Ideal for students preparing for chemistry exams.
Chemistry12
Understanding Molecular Polarity
Explore the concepts of bond polarity, dipole moments, and molecular shapes. This summary covers polar and non-polar molecules, including examples like water (H2O) and ammonia (NH3), and explains how molecular geometry affects overall polarity. Ideal for students studying chemistry.
Chemistry12
Chemistry of Bonding
Explore the fundamental concepts of atomic structure, ionic and covalent bonding, and the properties of materials. This summary covers nanoparticles, giant covalent structures, metallic bonding, and the behavior of different compounds, providing essential insights for chemistry students. Ideal for exam preparation and revision.
Chemistry12
Electrolysis Fundamentals
Explore the principles of electrolysis, including redox reactions, half-reactions, and the roles of anodes and cathodes. This summary covers key concepts such as electrolytic cells, Faraday's laws, and the significance of electrolytes in conducting electricity. Ideal for students preparing for exams or seeking a clear understanding of electrolysis processes.
Chemistry12
gcse | chemistry: bonding, structure, & properties of matter
grade 7+ gcse combined science notes
Chemistry12
Bonding & Intermolecular Forces
Comprehensive A Level Chemistry summary covering key concepts of bonding types, molecular shapes, electronegativity, and intermolecular forces. Understand ionic, covalent, and dative bonds, along with their properties and effects on molecular behavior. Ideal for exam preparation and revision.
Chemistry12
Most popular content: Hydrogen Bonding
Most popular content in Chemistry
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user