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Maddy Freeman
13/12/2025
Chemistry
GCSE AQA topic 2
124
•
13 Dec 2025
•
Understanding AQA GCSE Topic 2: Bonding, Structure, and Material Properties
Maddy Freeman
@maddyfreeman
1 / 10
Topic Introduction - Bonding, Structure and Properties
You're about to dive into one of chemistry's most fundamental topics. Understanding how atoms stick together will help you predict why materials behave the way they do.
This topic covers ionic bonding - the glue that holds many everyday compounds together, from table salt to the chalk on your whiteboard. Master these concepts and you'll find the rest of chemistry much easier to understand.
Quick Tip: Think of ionic bonding like magnets - opposites attract and create surprisingly strong connections!
What is Ionic Bonding?
Ionic bonding is basically nature's way of creating super-strong attractions between atoms. It happens when electrons jump from one atom to another, creating charged particles called ions.
Think of it as the electrostatic attraction between positive and negative ions - like how your socks stick to your jumper after coming out of the tumble dryer, but much stronger! This attraction is what holds ionic compounds together.
The strength of this bond explains why many ionic compounds are tough cookies that don't break apart easily.
Remember: Opposites attract! Positive ions are drawn to negative ions with serious force.
How Ionic Compounds Stay Together
Ionic compounds don't just stick together randomly - they organise themselves into a giant lattice structure. Picture a massive 3D framework that extends in all directions, like an endless jungle gym.
This regular, repeating pattern maximises the attractions between positive and negative ions whilst minimising repulsion between like charges. Every positive ion is surrounded by negative ions, and vice versa.
The electrostatic attractions throughout this lattice create incredibly stable structures that require lots of energy to break apart.
Visual Tip: Think of it like a perfectly organised dance where everyone knows exactly where to stand!
Properties of Ionic Substances
Ionic compounds have some pretty predictable properties that make perfect sense once you understand their structure. They have high melting and boiling points because those electrostatic forces are seriously strong - you need loads of energy to break them apart.
Here's something that catches many students out: ionic compounds don't conduct electricity when solid because the ions are locked in fixed positions in the lattice. However, when you melt them or dissolve them in water, the ions become free to move and can carry electrical current.
This explains why you can't electrocute yourself with solid salt, but salt water is a different story entirely!
Exam Tip: Always explain conductivity in terms of whether ions can move or not - it's a guaranteed mark!
Common Ions and Formula Writing
You'll need to recognise common ions for your exams. Positive ions include Na⁺, Mg²⁺, Al³⁺, Ca²⁺, and Rb⁺. Negative ions include Cl⁻ (chloride), Br⁻ (bromide), SO₄²⁻ (sulfate), NO₃⁻ (nitrate), and OH⁻ (hydroxide).
The golden rule for writing ionic formulas is that compounds must be electrically neutral. The positive and negative charges must balance out perfectly - like a perfectly balanced see-saw.
If you've got Mg²⁺ and Cl⁻, you need two chloride ions to balance one magnesium ion, giving you MgCl₂.
Memory Trick: Think "positive + negative = zero" - the charges must cancel out completely!
How Ionic Compounds Form
Let's look at magnesium oxide (MgO) as a perfect example of ionic compound formation. Magnesium atoms lose two electrons to become Mg²⁺ ions, while oxygen atoms gain two electrons to become O²⁻ ions.
This electron transfer creates the charged particles that then attract each other with tremendous force. The magnesium ion has a positive charge because it's lost electrons, whilst the oxide ion is negative because it's gained electrons.
The result? A incredibly stable compound that can withstand high temperatures - which is why magnesium oxide is used in fire-resistant materials.
Key Point: Ionic bonding is all about electron transfer - metals lose electrons, non-metals gain them!
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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
Understanding AQA GCSE Topic 2: Bonding, Structure, and Material Properties
Maddy Freeman
@maddyfreeman
Ever wondered why salt dissolves in water but doesn't melt on your chip shop chips? It's all down to ionic bonding - one of the most important types of chemical bonding you'll need to master for your GCSE Chemistry exam.
Topic Introduction - Bonding, Structure and Properties
You're about to dive into one of chemistry's most fundamental topics. Understanding how atoms stick together will help you predict why materials behave the way they do.
This topic covers ionic bonding - the glue that holds many everyday compounds together, from table salt to the chalk on your whiteboard. Master these concepts and you'll find the rest of chemistry much easier to understand.
Quick Tip: Think of ionic bonding like magnets - opposites attract and create surprisingly strong connections!
Sign up to see the contentIt's free!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
What is Ionic Bonding?
Ionic bonding is basically nature's way of creating super-strong attractions between atoms. It happens when electrons jump from one atom to another, creating charged particles called ions.
Think of it as the electrostatic attraction between positive and negative ions - like how your socks stick to your jumper after coming out of the tumble dryer, but much stronger! This attraction is what holds ionic compounds together.
The strength of this bond explains why many ionic compounds are tough cookies that don't break apart easily.
Remember: Opposites attract! Positive ions are drawn to negative ions with serious force.
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
How Ionic Compounds Stay Together
Ionic compounds don't just stick together randomly - they organise themselves into a giant lattice structure. Picture a massive 3D framework that extends in all directions, like an endless jungle gym.
This regular, repeating pattern maximises the attractions between positive and negative ions whilst minimising repulsion between like charges. Every positive ion is surrounded by negative ions, and vice versa.
The electrostatic attractions throughout this lattice create incredibly stable structures that require lots of energy to break apart.
Visual Tip: Think of it like a perfectly organised dance where everyone knows exactly where to stand!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Properties of Ionic Substances
Ionic compounds have some pretty predictable properties that make perfect sense once you understand their structure. They have high melting and boiling points because those electrostatic forces are seriously strong - you need loads of energy to break them apart.
Here's something that catches many students out: ionic compounds don't conduct electricity when solid because the ions are locked in fixed positions in the lattice. However, when you melt them or dissolve them in water, the ions become free to move and can carry electrical current.
This explains why you can't electrocute yourself with solid salt, but salt water is a different story entirely!
Exam Tip: Always explain conductivity in terms of whether ions can move or not - it's a guaranteed mark!
Sign up to see the contentIt's free!
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Common Ions and Formula Writing
You'll need to recognise common ions for your exams. Positive ions include Na⁺, Mg²⁺, Al³⁺, Ca²⁺, and Rb⁺. Negative ions include Cl⁻ (chloride), Br⁻ (bromide), SO₄²⁻ (sulfate), NO₃⁻ (nitrate), and OH⁻ (hydroxide).
The golden rule for writing ionic formulas is that compounds must be electrically neutral. The positive and negative charges must balance out perfectly - like a perfectly balanced see-saw.
If you've got Mg²⁺ and Cl⁻, you need two chloride ions to balance one magnesium ion, giving you MgCl₂.
Memory Trick: Think "positive + negative = zero" - the charges must cancel out completely!
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How Ionic Compounds Form
Let's look at magnesium oxide (MgO) as a perfect example of ionic compound formation. Magnesium atoms lose two electrons to become Mg²⁺ ions, while oxygen atoms gain two electrons to become O²⁻ ions.
This electron transfer creates the charged particles that then attract each other with tremendous force. The magnesium ion has a positive charge because it's lost electrons, whilst the oxide ion is negative because it's gained electrons.
The result? A incredibly stable compound that can withstand high temperatures - which is why magnesium oxide is used in fire-resistant materials.
Key Point: Ionic bonding is all about electron transfer - metals lose electrons, non-metals gain them!
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Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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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?
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Is Knowunity really free of charge?
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Most popular content: Properties of Matter
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English - inspector calls quotes and analysis
Quotes from every main character
English Literature10
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