Subjects
Maths
Biology
Chemistry
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
1l the quest for political stability: germany, 1871-1991
Britain & the wider world: 1745 -1901
The cold war
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
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Chemistry
3 Dec 2025
83
2 pages
Sophieeee ๐๐๐๐บ๐ @sophiesnotes
The first 20 elements in the periodic table aren't just randomly arranged - they're organised by atomic number... Show more
The periodic table arranges elements in horizontal rows (periods) by increasing atomic number and vertical columns (groups) by similar properties. Elements in the same group behave similarly because they have the same number of outer electrons, making it dead easy to predict how they'll react.
Covalent molecular structures are made up of separate molecules held together by weak intermolecular forces. The actual covalent bonds form when non-metal atoms share electrons to achieve a stable outer electron arrangement (like noble gases). Think of it as atoms "holding hands" with shared electrons.
Most covalent molecular elements are diatomic (two atoms joined together) hydrogen (Hโ), nitrogen (Nโ), oxygen (Oโ), fluorine (Fโ), and chlorine (Clโ). Some elements form larger molecules like phosphorus (Pโ) and sulfur (Sโ).
Quick Tip Covalent molecular elements have low melting points, low densities, and don't conduct electricity because there are no free-moving charged particles.
Covalent network structures are completely different beasts - they're giant lattices where atoms are connected by strong covalent bonds throughout the entire structure. Boron, carbon, and silicon form these networks, resulting in incredibly high melting points because you'd need to break loads of strong bonds to melt them.
Metallic structures consist of positive metal ions surrounded by a "sea" of delocalised electrons. The metals lithium, beryllium, sodium, magnesium, aluminium, and calcium all have this structure. These free-moving electrons make metals excellent electrical conductors - it's like having a motorway for electric current.
Monatomic structures are the loners of chemistry - individual atoms held together only by weak intermolecular forces. The noble gases (helium, neon, argon) exist this way because they already have full outer electron shells, so they don't bother forming bonds with other atoms.
Remember The stronger the bonds holding a structure together, the higher its melting point will be. Network > metallic > molecular > monatomic.
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 key concepts of periodicity in chemistry, including trends in ionization energy, electron configuration, and the properties of metals, non-metals, and giant covalent structures. This comprehensive summary covers essential topics such as the structure of the periodic table, the significance of Mendeleev's contributions, and the characteristics of materials like graphene and silicon. Ideal for A-Level students preparing for exams.
ChemistryExplore key concepts in enthalpy, reaction kinetics, and chemical bonding. This study note covers Hess's Law, activation energy, collision theory, energy distribution curves, and various types of chemical bonds, including ionic and covalent. Ideal for Higher Chemistry students seeking to deepen their understanding of thermodynamics and reaction rates.
ChemistryExplore the key concepts of metallic bonding, including the role of delocalized electrons, the impact on melting and boiling points, and the properties of metallic solids. This summary covers the structure of metallic lattices, conductivity, malleability, and solubility, providing a comprehensive overview for students studying chemical bonding.
ChemistryExplore the key concepts of metallic bonding, including the role of delocalised electrons, the properties of metals, and factors affecting bond strength. This summary covers the structure, conductivity, malleability, and high melting points of metals, providing essential insights for students studying metallic bonding in chemistry.
ChemistryExplore key concepts in chemical bonding and energetics with this comprehensive summary. Topics include ionization energy, bond enthalpy, reaction rates, and intermolecular forces. Ideal for Higher Chemistry students preparing for exams, this resource covers essential principles such as Hess's Law, activation energy, and the impact of temperature and concentration on reaction kinetics.
ChemistryExplore the various types of chemical bonds including covalent, ionic, and metallic bonds. Understand their properties, structures, and the role of electronegativity and intermolecular forces. This summary is essential for WJEC AS Level Chemistry students preparing for exams.
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
The first 20 elements in the periodic table aren't just randomly arranged - they're organised by atomic number and grouped by similar properties. Understanding how these elements bond and structure themselves is crucial for predicting their behaviour and properties.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The periodic table arranges elements in horizontal rows (periods) by increasing atomic number and vertical columns (groups) by similar properties. Elements in the same group behave similarly because they have the same number of outer electrons, making it dead easy to predict how they'll react.
Covalent molecular structures are made up of separate molecules held together by weak intermolecular forces. The actual covalent bonds form when non-metal atoms share electrons to achieve a stable outer electron arrangement (like noble gases). Think of it as atoms "holding hands" with shared electrons.
Most covalent molecular elements are diatomic (two atoms joined together): hydrogen (Hโ), nitrogen (Nโ), oxygen (Oโ), fluorine (Fโ), and chlorine (Clโ). Some elements form larger molecules like phosphorus (Pโ) and sulfur (Sโ).
Quick Tip: Covalent molecular elements have low melting points, low densities, and don't conduct electricity because there are no free-moving charged particles.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Covalent network structures are completely different beasts - they're giant lattices where atoms are connected by strong covalent bonds throughout the entire structure. Boron, carbon, and silicon form these networks, resulting in incredibly high melting points because you'd need to break loads of strong bonds to melt them.
Metallic structures consist of positive metal ions surrounded by a "sea" of delocalised electrons. The metals lithium, beryllium, sodium, magnesium, aluminium, and calcium all have this structure. These free-moving electrons make metals excellent electrical conductors - it's like having a motorway for electric current.
Monatomic structures are the loners of chemistry - individual atoms held together only by weak intermolecular forces. The noble gases (helium, neon, argon) exist this way because they already have full outer electron shells, so they don't bother forming bonds with other atoms.
Remember: The stronger the bonds holding a structure together, the higher its melting point will be. Network > metallic > molecular > monatomic.
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 key concepts of periodicity in chemistry, including trends in ionization energy, electron configuration, and the properties of metals, non-metals, and giant covalent structures. This comprehensive summary covers essential topics such as the structure of the periodic table, the significance of Mendeleev's contributions, and the characteristics of materials like graphene and silicon. Ideal for A-Level students preparing for exams.
ChemistryExplore key concepts in enthalpy, reaction kinetics, and chemical bonding. This study note covers Hess's Law, activation energy, collision theory, energy distribution curves, and various types of chemical bonds, including ionic and covalent. Ideal for Higher Chemistry students seeking to deepen their understanding of thermodynamics and reaction rates.
ChemistryExplore the key concepts of metallic bonding, including the role of delocalized electrons, the impact on melting and boiling points, and the properties of metallic solids. This summary covers the structure of metallic lattices, conductivity, malleability, and solubility, providing a comprehensive overview for students studying chemical bonding.
ChemistryExplore the key concepts of metallic bonding, including the role of delocalised electrons, the properties of metals, and factors affecting bond strength. This summary covers the structure, conductivity, malleability, and high melting points of metals, providing essential insights for students studying metallic bonding in chemistry.
ChemistryExplore key concepts in chemical bonding and energetics with this comprehensive summary. Topics include ionization energy, bond enthalpy, reaction rates, and intermolecular forces. Ideal for Higher Chemistry students preparing for exams, this resource covers essential principles such as Hess's Law, activation energy, and the impact of temperature and concentration on reaction kinetics.
ChemistryExplore the various types of chemical bonds including covalent, ionic, and metallic bonds. Understand their properties, structures, and the role of electronegativity and intermolecular forces. This summary is essential for WJEC AS Level Chemistry students preparing for exams.
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
