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issy
05/12/2025
Chemistry
c1 - atomic structure & the periodic table
203
•
5 Dec 2025
•
C1: Atomic Structure & Periodic Table Overview
issy
@issy.studies
Atomic Structure and Chemical Bonding
Atoms are the tiny building blocks of everything - they're made up of protons (positive charge), neutrons (no charge), and electrons (negative charge). The protons and neutrons hang out together in the nucleus, while electrons zoom around in shells outside.
Here's what makes atoms interesting: the atomic number tells you how many protons an atom has, and this determines what element it is. The mass number is the total number of protons and neutrons combined. Isotopes are just different versions of the same element with different numbers of neutrons - same element, slightly different mass.
When atoms get together, they form molecules (held by chemical bonds) or compounds (two or more different elements). Mixtures are different - the substances aren't chemically stuck together, so you can separate them quite easily using methods like filtration or evaporation.
Quick Tip: Remember that electrons determine how atoms react with each other - it's all about filling up those outer shells!
Separating Mixtures Made Simple
You've got several tricks up your sleeve for separating mixtures. Filtration works brilliantly for getting insoluble solids out of liquids - just use filter paper and gravity does the work.
For evaporation, you heat up the mixture so the liquid evaporates and leaves the solid behind. Crystallisation is the gentler cousin - you heat it slowly (often using a water bath) until crystals start forming, then let it cool down naturally.
Distillation is your go-to for separating liquids from solutions. The liquid evaporates, travels through a tube, condenses back into liquid, and you collect it separately. Fractional distillation takes this further - it separates different liquids based on their different boiling points using a special column.
The Periodic Table: Your Chemical Map
The periodic table isn't just a random arrangement - it's pure genius! Dmitri Mendeleev organised elements by increasing atomic number, and elements in the same group (column) have similar properties because they have the same number of electrons in their outer shell.
Group 1 metals (like lithium, sodium, potassium) are the show-offs of chemistry - they react vigorously with water and oxygen, get more reactive as you go down the group, and always form positive ions. Group 7 halogens (fluorine, chlorine, bromine, iodine) are the opposite - they form negative ions and become less reactive as you go down.
Metals hang out on the left side of the table and are brilliant conductors with high melting points. Non-metals live on the right side, are rubbish conductors, and often form covalent bonds by sharing electrons. The noble gases in Group 0 are the loners - they've got full outer shells so they barely react with anything.
Remember: The group number tells you how many electrons are in the outer shell - that's what determines how an element behaves!
Transition metals are the multi-talented ones in the middle - they can form multiple types of ions and often work as catalysts. Understanding where elements live on the periodic table instantly tells you how they'll behave in reactions.
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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
C1: Atomic Structure & Periodic Table Overview
issy
@issy.studies
Ever wonder what makes up absolutely everything around you? From the air you breathe to your mobile phone, it all comes down to atoms and how they're organised. Understanding atoms and the periodic table is like having the ultimate cheat... Show more
Atomic Structure and Chemical Bonding
Atoms are the tiny building blocks of everything - they're made up of protons (positive charge), neutrons (no charge), and electrons (negative charge). The protons and neutrons hang out together in the nucleus, while electrons zoom around in shells outside.
Here's what makes atoms interesting: the atomic number tells you how many protons an atom has, and this determines what element it is. The mass number is the total number of protons and neutrons combined. Isotopes are just different versions of the same element with different numbers of neutrons - same element, slightly different mass.
When atoms get together, they form molecules (held by chemical bonds) or compounds (two or more different elements). Mixtures are different - the substances aren't chemically stuck together, so you can separate them quite easily using methods like filtration or evaporation.
Quick Tip: Remember that electrons determine how atoms react with each other - it's all about filling up those outer shells!
Separating Mixtures Made Simple
You've got several tricks up your sleeve for separating mixtures. Filtration works brilliantly for getting insoluble solids out of liquids - just use filter paper and gravity does the work.
For evaporation, you heat up the mixture so the liquid evaporates and leaves the solid behind. Crystallisation is the gentler cousin - you heat it slowly (often using a water bath) until crystals start forming, then let it cool down naturally.
Distillation is your go-to for separating liquids from solutions. The liquid evaporates, travels through a tube, condenses back into liquid, and you collect it separately. Fractional distillation takes this further - it separates different liquids based on their different boiling points using a special column.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Periodic Table: Your Chemical Map
The periodic table isn't just a random arrangement - it's pure genius! Dmitri Mendeleev organised elements by increasing atomic number, and elements in the same group (column) have similar properties because they have the same number of electrons in their outer shell.
Group 1 metals (like lithium, sodium, potassium) are the show-offs of chemistry - they react vigorously with water and oxygen, get more reactive as you go down the group, and always form positive ions. Group 7 halogens (fluorine, chlorine, bromine, iodine) are the opposite - they form negative ions and become less reactive as you go down.
Metals hang out on the left side of the table and are brilliant conductors with high melting points. Non-metals live on the right side, are rubbish conductors, and often form covalent bonds by sharing electrons. The noble gases in Group 0 are the loners - they've got full outer shells so they barely react with anything.
Remember: The group number tells you how many electrons are in the outer shell - that's what determines how an element behaves!
Transition metals are the multi-talented ones in the middle - they can form multiple types of ions and often work as catalysts. Understanding where elements live on the periodic table instantly tells you how they'll behave in reactions.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
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Is Knowunity really free of charge?
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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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
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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