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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
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
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Chemistry
30 Nov 2025
281
2 pages
Ever wondered what makes up everything around you? Atoms are the tiny building blocks of all matter, and... Show more
Think of an atom as the smallest piece of an element that can still take part in chemical reactions. Here's the surprising bit - atoms are mostly empty space! It's a bit like a football stadium with just a marble at the centre.
All the mass of an atom is packed into the tiny nucleus at its centre. This nucleus contains two types of particles protons (positively charged) and neutrons (no charge). Both have a relative mass of 1, making them the heavyweight champions of the atomic world.
Electrons zoom around this nucleus like planets orbiting the sun, but they're incredibly light - about 2000 times lighter than protons or neutrons. These negatively charged particles create a 'cloud' around the nucleus. The electrostatic attraction between the positive nucleus and negative electrons is what keeps the whole atom together.
Key Point Atoms are neutral overall because they have equal numbers of protons and electrons, so the positive and negative charges cancel out perfectly.
When atoms gain or lose electrons, they become ions - charged particles that behave very differently. Cations are positively charged because they've lost electrons (fewer electrons than protons). Anions are negatively charged because they've gained extra electrons.
Isotopes are like identical twins with different weights - they're atoms of the same element with identical numbers of protons and electrons, but different numbers of neutrons. This means they have the same atomic number but different mass numbers.
Here's what's brilliant about isotopes they have identical chemical properties because they have the same number of electrons in their outer shells. Since electrons control chemical reactions, isotopes react in exactly the same way. However, their physical properties differ slightly because extra neutrons add mass without changing the chemistry.
Remember Neutrons are like adding extra weight to a car - it makes it heavier and affects things like density, but it doesn't change how the engine works!
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 key concepts of chemical bonding in Higher Chemistry Unit 1. This summary covers covalent molecular and network structures, ionic lattices, monatomic elements, and carbon allotropes like graphite and diamond. Understand the properties, melting points, and conductivity of various bonding types with detailed insights.
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.
ChemistryExplore 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.
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
Ever wondered what makes up everything around you? Atoms are the tiny building blocks of all matter, and understanding their structure is crucial for mastering chemistry. Let's break down how these incredibly small particles work and why they behave the... Show more
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Think of an atom as the smallest piece of an element that can still take part in chemical reactions. Here's the surprising bit - atoms are mostly empty space! It's a bit like a football stadium with just a marble at the centre.
All the mass of an atom is packed into the tiny nucleus at its centre. This nucleus contains two types of particles: protons (positively charged) and neutrons (no charge). Both have a relative mass of 1, making them the heavyweight champions of the atomic world.
Electrons zoom around this nucleus like planets orbiting the sun, but they're incredibly light - about 2000 times lighter than protons or neutrons. These negatively charged particles create a 'cloud' around the nucleus. The electrostatic attraction between the positive nucleus and negative electrons is what keeps the whole atom together.
Key Point: Atoms are neutral overall because they have equal numbers of protons and electrons, so the positive and negative charges cancel out perfectly.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When atoms gain or lose electrons, they become ions - charged particles that behave very differently. Cations are positively charged because they've lost electrons (fewer electrons than protons). Anions are negatively charged because they've gained extra electrons.
Isotopes are like identical twins with different weights - they're atoms of the same element with identical numbers of protons and electrons, but different numbers of neutrons. This means they have the same atomic number but different mass numbers.
Here's what's brilliant about isotopes: they have identical chemical properties because they have the same number of electrons in their outer shells. Since electrons control chemical reactions, isotopes react in exactly the same way. However, their physical properties differ slightly because extra neutrons add mass without changing the chemistry.
Remember: Neutrons are like adding extra weight to a car - it makes it heavier and affects things like density, but it doesn't change how the engine works!
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 chemical bonding in Higher Chemistry Unit 1. This summary covers covalent molecular and network structures, ionic lattices, monatomic elements, and carbon allotropes like graphite and diamond. Understand the properties, melting points, and conductivity of various bonding types with detailed insights.
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.
ChemistryExplore 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.
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