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Organisms respond to changes in their internal and external environments (a-level only)
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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
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Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
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2s the making of modern britain, 1951-2007
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Chemistry
29 Nov 2025
42
3 pages
Sophieeee ๐๐๐๐บ๐ @sophiesnotes
Understanding chemical bonding and structure is crucial for predicting how materials behave in everyday life. From why metals... Show more
Ever wondered why copper wires carry electricity whilst plastic doesn't? It's all about metallic bonding and those brilliant delocalised electrons that can move freely through the metal structure. Metals are fantastic conductors because these electrons aren't stuck to individual atoms.
Covalent molecular structures work completely differently - think of them as discrete groups of atoms that stick together to form molecules like oxygen (Oโ) or water. These structures typically have low melting and boiling points because the attraction between separate molecules is pretty weak.
However, things get interesting when polar molecules enter the picture. Compounds like iodine chloride have slightly higher boiling points than non-polar bromine because of permanent dipole attractions. When hydrogen bonding kicks in, you'll see dramatically higher melting and boiling points since it takes much more energy to separate these strongly attracted molecules.
Quick Tip If you see a molecular formula with a small number (like Oโ or Sโ), you're looking at a covalent molecular structure with relatively low melting points.
Covalent networks are the giants of the bonding world - imagine atoms linking up endlessly to create massive structures with no definite size. Only carbon, silicon, and boron can pull this off, and breaking these networks requires smashing all those strong covalent bonds, which explains their sky-high melting points.
Ionic compounds are always solid at room temperature because their ionic bonds create incredibly strong lattice structures. The cool thing about ionic compounds is their conducting ability - they're brilliant conductors when dissolved in water or melted because the ions can move freely and carry current.
But here's the catch solid ionic compounds don't conduct electricity at all. The ions are essentially "locked" in their lattice positions and can't move to carry current. When you run electricity through ionic solutions, you'll get electrolysis - a chemical reaction that changes the substances at the electrodes.
Monatomic elements (the noble gases in Group 0) are the loners of chemistry. These single atoms only experience weak London dispersion forces between them, resulting in low densities and melting points, plus they're rubbish at conducting electricity.
Remember Ionic compounds conduct when mobile but not when solid - the ions need to move freely to carry current.
Fullerenes are fascinating carbon molecules that look like football-shaped cages. Despite being molecular structures (not networks), their large size creates stronger dispersion forces than smaller molecules, making them solid at room temperature whilst still having relatively low melting points.
Graphite showcases carbon's versatility with its layered structure where each carbon forms three covalent bonds. The layers stick together through weak van der Waals forces, whilst delocalised electrons between layers make graphite an excellent conductor - that's why it's perfect for electrodes and pencil lead that leaves marks on paper.
The weak forces between graphite's layers make it incredibly soft and slippery, explaining why it works brilliantly as a lubricant. You can literally slide the layers past each other with minimal effort.
Diamond represents carbon at its toughest - every carbon atom forms four bonds in a rigid tetrahedral structure. This creates the hardest natural substance known, making diamond invaluable for cutting tools and drill bits. However, all those electrons are locked in bonds, so diamond can't conduct electricity at all.
Key Insight Same element, completely different properties! Graphite conducts and is soft, whilst diamond doesn't conduct but is incredibly hard - structure determines everything.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
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Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the fundamentals of atomic structure, ions, and isotopes in this detailed summary. Understand how cations and anions form, the significance of isotopes in chemistry, and the role of subatomic particles. Ideal for OCR A Level Chemistry students seeking clarity on these essential concepts.
ChemistryExplore the essential concepts of periodic trends, chemical bonding, and molecular properties in this comprehensive summary. Understand key topics such as electronegativity, ionization energy, and various types of intermolecular forces including hydrogen bonding and London dispersion forces. Ideal for higher chemistry students preparing for exams.
ChemistryExplore the fundamentals of chemical bonding, including ionic and covalent bonds, intermolecular forces, and molecular structures. This comprehensive summary covers key concepts such as hydrogen bonding, Van der Waals forces, and the properties of different bonding types, making it an essential resource for AQA AS Chemistry students.
ChemistryExplore the fundamentals of electrons and chemical bonding, including ionic and covalent bonds, subshell notation, and the principles of orbital filling. This summary covers key concepts such as bond enthalpy, the octet rule, and the structure of ionic compounds, making it essential for A-level Physical Chemistry students.
ChemistryExplore 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.
ChemistryComprehensive 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.
ChemistryApp Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Sophieeee ๐๐๐๐บ๐
@sophiesnotes
Understanding chemical bonding and structure is crucial for predicting how materials behave in everyday life. From why metals conduct electricity to why diamond is so hard, it all comes down to how atoms stick together and arrange themselves.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered why copper wires carry electricity whilst plastic doesn't? It's all about metallic bonding and those brilliant delocalised electrons that can move freely through the metal structure. Metals are fantastic conductors because these electrons aren't stuck to individual atoms.
Covalent molecular structures work completely differently - think of them as discrete groups of atoms that stick together to form molecules like oxygen (Oโ) or water. These structures typically have low melting and boiling points because the attraction between separate molecules is pretty weak.
However, things get interesting when polar molecules enter the picture. Compounds like iodine chloride have slightly higher boiling points than non-polar bromine because of permanent dipole attractions. When hydrogen bonding kicks in, you'll see dramatically higher melting and boiling points since it takes much more energy to separate these strongly attracted molecules.
Quick Tip: If you see a molecular formula with a small number (like Oโ or Sโ), you're looking at a covalent molecular structure with relatively low melting points.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Covalent networks are the giants of the bonding world - imagine atoms linking up endlessly to create massive structures with no definite size. Only carbon, silicon, and boron can pull this off, and breaking these networks requires smashing all those strong covalent bonds, which explains their sky-high melting points.
Ionic compounds are always solid at room temperature because their ionic bonds create incredibly strong lattice structures. The cool thing about ionic compounds is their conducting ability - they're brilliant conductors when dissolved in water or melted because the ions can move freely and carry current.
But here's the catch: solid ionic compounds don't conduct electricity at all. The ions are essentially "locked" in their lattice positions and can't move to carry current. When you run electricity through ionic solutions, you'll get electrolysis - a chemical reaction that changes the substances at the electrodes.
Monatomic elements (the noble gases in Group 0) are the loners of chemistry. These single atoms only experience weak London dispersion forces between them, resulting in low densities and melting points, plus they're rubbish at conducting electricity.
Remember: Ionic compounds conduct when mobile but not when solid - the ions need to move freely to carry current.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Fullerenes are fascinating carbon molecules that look like football-shaped cages. Despite being molecular structures (not networks), their large size creates stronger dispersion forces than smaller molecules, making them solid at room temperature whilst still having relatively low melting points.
Graphite showcases carbon's versatility with its layered structure where each carbon forms three covalent bonds. The layers stick together through weak van der Waals forces, whilst delocalised electrons between layers make graphite an excellent conductor - that's why it's perfect for electrodes and pencil lead that leaves marks on paper.
The weak forces between graphite's layers make it incredibly soft and slippery, explaining why it works brilliantly as a lubricant. You can literally slide the layers past each other with minimal effort.
Diamond represents carbon at its toughest - every carbon atom forms four bonds in a rigid tetrahedral structure. This creates the hardest natural substance known, making diamond invaluable for cutting tools and drill bits. However, all those electrons are locked in bonds, so diamond can't conduct electricity at all.
Key Insight: Same element, completely different properties! Graphite conducts and is soft, whilst diamond doesn't conduct but is incredibly hard - structure determines everything.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
2
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the fundamentals of atomic structure, ions, and isotopes in this detailed summary. Understand how cations and anions form, the significance of isotopes in chemistry, and the role of subatomic particles. Ideal for OCR A Level Chemistry students seeking clarity on these essential concepts.
ChemistryExplore the essential concepts of periodic trends, chemical bonding, and molecular properties in this comprehensive summary. Understand key topics such as electronegativity, ionization energy, and various types of intermolecular forces including hydrogen bonding and London dispersion forces. Ideal for higher chemistry students preparing for exams.
ChemistryExplore the fundamentals of chemical bonding, including ionic and covalent bonds, intermolecular forces, and molecular structures. This comprehensive summary covers key concepts such as hydrogen bonding, Van der Waals forces, and the properties of different bonding types, making it an essential resource for AQA AS Chemistry students.
ChemistryExplore the fundamentals of electrons and chemical bonding, including ionic and covalent bonds, subshell notation, and the principles of orbital filling. This summary covers key concepts such as bond enthalpy, the octet rule, and the structure of ionic compounds, making it essential for A-level Physical Chemistry students.
ChemistryExplore 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.
ChemistryComprehensive 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.
ChemistryApp Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Sociology