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Britain & the wider world: 1745 -1901
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Chemistry
10 Dec 2025
123
2 pages
Bridget Gyabeng @bridgetgyabeng_etbo
Chemistry starts to make sense when you understand what atoms are made of and how they stick together.... Show more
Atoms rarely exist alone - they're social creatures that love to bond with others to become more stable. There are two main ways they do this, and understanding them helps explain why different substances behave so differently.
Ionic bonding happens when metals meet non-metals in a dramatic electron transfer. The metal atoms lose electrons and become positive ions, whilst non-metals gain those electrons and become negative ions. These oppositely charged ions then attract each other with a powerful electrostatic force - that's your ionic bond.
Covalent bonds work completely differently - instead of transferring electrons, non-metal atoms decide to share them. When two atoms share a pair of electrons, they both get to complete their outer shells and everyone's happy.
The type of bonding affects how substances behave. Ionic compounds like sodium chloride form crystals with high melting points, whilst covalent molecules often have much lower melting and boiling points because the bonds between molecules are weaker.
Remember Metals + Non-metals = Ionic bonding (electron transfer). Non-metals + Non-metals = Covalent bonding (electron sharing).
Every atom is like a tiny solar system with a nucleus at its centre containing protons and neutrons, whilst electrons whizz around in shells. Think of it as the atom's control centre surrounded by protective layers.
The three main particles have different jobs protons carry a positive charge (+1), electrons carry a negative charge (-1), and neutrons are neutral with no charge. Protons and neutrons are roughly the same size, but electrons are incredibly small in comparison.
Here's the clever bit - atoms always have equal numbers of protons and electrons, so their charges cancel out perfectly. This means atoms are electrically neutral overall, even though they contain charged particles.
The atomic number tells you how many protons an element has, and this never changes. To find neutrons, simply subtract the atomic number from the mass number. Isotopes are atoms of the same element with different numbers of neutrons - they're like identical twins with different weights.
Quick Tip Remember that the atomic number equals both the number of protons AND electrons in a neutral atom!
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 – all at your fingertips.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the reactivity series of metals, oxidation and reduction processes, and the formation of salts through various chemical reactions. This summary covers key concepts such as displacement reactions, redox reactions, and the extraction of metals, tailored for AQA GCSE Combined Science Chemistry students. Understand how metals react with water, acids, and their oxides, along with essential equations and definitions.
ChemistryExplore the fundamentals of chemical changes, including strong and weak acids, reactivity of metals, and redox reactions. This summary covers the processes of making salts, the reactivity series, and the principles of oxidation and reduction. Ideal for AQA chemistry students preparing for exams.
ChemistryExplore the process of electrolysis, including key concepts such as oxidation, reduction, and the roles of the anode and cathode. This summary provides a clear overview of how electric current decomposes ionic compounds in electrolytic cells, supported by diagrams for better understanding.
ChemistryDive into the fundamentals of electrolysis, covering key concepts such as anodes, cathodes, and the role of electrolytes. This summary highlights the processes involved in both molten and aqueous solutions, including the production of gases and metal deposits. Ideal for IGCSE/GCSE Chemistry students seeking a clear understanding of electrolysis and its applications in metal purification and reactions. Includes essential terms like Faraday's laws and electrolytic cells.
ChemistryExplore the process of electrolysis for metal extraction, focusing on aluminium and lead. Understand key concepts such as electrodes, electrolytes, and half-reactions. This summary covers the principles of electrolysis, including the roles of the cathode and anode, and the reactions involved in both molten and aqueous solutions. Ideal for AQA GCSE Chemistry students preparing for paper 1.
ChemistryExplore key concepts of electrolysis, including ionic and covalent bonding, Faraday's Law, and the production of metals like aluminum. This resource features exam questions and answers to enhance your understanding of electrochemical processes and their applications in metal extraction and alloy formation.
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 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
Bridget Gyabeng
@bridgetgyabeng_etbo
Chemistry starts to make sense when you understand what atoms are made of and how they stick together. These fundamental concepts explain everything from why salt dissolves in water to how your DNA holds together.
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Join milions of students
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Atoms rarely exist alone - they're social creatures that love to bond with others to become more stable. There are two main ways they do this, and understanding them helps explain why different substances behave so differently.
Ionic bonding happens when metals meet non-metals in a dramatic electron transfer. The metal atoms lose electrons and become positive ions, whilst non-metals gain those electrons and become negative ions. These oppositely charged ions then attract each other with a powerful electrostatic force - that's your ionic bond.
Covalent bonds work completely differently - instead of transferring electrons, non-metal atoms decide to share them. When two atoms share a pair of electrons, they both get to complete their outer shells and everyone's happy.
The type of bonding affects how substances behave. Ionic compounds like sodium chloride form crystals with high melting points, whilst covalent molecules often have much lower melting and boiling points because the bonds between molecules are weaker.
Remember: Metals + Non-metals = Ionic bonding (electron transfer). Non-metals + Non-metals = Covalent bonding (electron sharing).
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Every atom is like a tiny solar system with a nucleus at its centre containing protons and neutrons, whilst electrons whizz around in shells. Think of it as the atom's control centre surrounded by protective layers.
The three main particles have different jobs: protons carry a positive charge (+1), electrons carry a negative charge (-1), and neutrons are neutral with no charge. Protons and neutrons are roughly the same size, but electrons are incredibly small in comparison.
Here's the clever bit - atoms always have equal numbers of protons and electrons, so their charges cancel out perfectly. This means atoms are electrically neutral overall, even though they contain charged particles.
The atomic number tells you how many protons an element has, and this never changes. To find neutrons, simply subtract the atomic number from the mass number. Isotopes are atoms of the same element with different numbers of neutrons - they're like identical twins with different weights.
Quick Tip: Remember that the atomic number equals both the number of protons AND electrons in a neutral atom!
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 – all at your fingertips.
8
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the reactivity series of metals, oxidation and reduction processes, and the formation of salts through various chemical reactions. This summary covers key concepts such as displacement reactions, redox reactions, and the extraction of metals, tailored for AQA GCSE Combined Science Chemistry students. Understand how metals react with water, acids, and their oxides, along with essential equations and definitions.
ChemistryExplore the fundamentals of chemical changes, including strong and weak acids, reactivity of metals, and redox reactions. This summary covers the processes of making salts, the reactivity series, and the principles of oxidation and reduction. Ideal for AQA chemistry students preparing for exams.
ChemistryExplore the process of electrolysis, including key concepts such as oxidation, reduction, and the roles of the anode and cathode. This summary provides a clear overview of how electric current decomposes ionic compounds in electrolytic cells, supported by diagrams for better understanding.
ChemistryDive into the fundamentals of electrolysis, covering key concepts such as anodes, cathodes, and the role of electrolytes. This summary highlights the processes involved in both molten and aqueous solutions, including the production of gases and metal deposits. Ideal for IGCSE/GCSE Chemistry students seeking a clear understanding of electrolysis and its applications in metal purification and reactions. Includes essential terms like Faraday's laws and electrolytic cells.
ChemistryExplore the process of electrolysis for metal extraction, focusing on aluminium and lead. Understand key concepts such as electrodes, electrolytes, and half-reactions. This summary covers the principles of electrolysis, including the roles of the cathode and anode, and the reactions involved in both molten and aqueous solutions. Ideal for AQA GCSE Chemistry students preparing for paper 1.
ChemistryExplore key concepts of electrolysis, including ionic and covalent bonding, Faraday's Law, and the production of metals like aluminum. This resource features exam questions and answers to enhance your understanding of electrochemical processes and their applications in metal extraction and alloy formation.
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 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
Sociology