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T
Tara Vidal
13/12/2025
Chemistry
Atomic structure
68
•
13 Dec 2025
•
Understanding Atomic Structure - GCSE Chemistry Chapter 1
T
Tara Vidal
@taravidal_jrny
1 / 3
Basic Chemistry Concepts and Separation Techniques
Ever wondered how scientists identify what's in your drink or separate oil from water? State symbols are your first clue - they tell you whether something is solid (s), liquid (l), gas (g), or dissolved in water, called aqueous (aq).
The Law of Conservation of Mass is chemistry's golden rule: matter can't be created or destroyed, only rearranged. This means in any chemical reaction, you'll always end up with the same total mass you started with. Understanding the difference between compounds (chemically bonded substances) and mixtures (just mixed together) helps explain why we can separate mixtures using physical methods.
You've got four main separation techniques in your toolkit: filtration for removing insoluble substances, crystallisation for separating dissolved solids from liquids by heating, chromatography for separating multiple solutes, and distillation for separating liquids from solids or liquids with different boiling points.
Key Tip: Remember that simple distillation works by evaporating then condensing, whilst fractional distillation uses different boiling points to separate liquid mixtures - perfect for separating crude oil!
Atomic Structure and the Periodic Table
Your understanding of atoms started with J.J. Thomson's discovery of electrons and his plum pudding model, which imagined electrons scattered randomly in a positive mass - like raisins in a pudding. However, the famous Gold Leaf Experiment completely changed this picture by firing alpha particles at gold foil.
The results were mind-blowing: most particles passed straight through (atoms are mostly empty space!), some deflected (the centre is positively charged), and some bounced back (the centre contains lots of mass). This proved atoms have a dense, positive nucleus surrounded by mostly empty space.
Mendeleev's periodic table organised elements by increasing atomic weight and cleverly left spaces for undiscovered elements. Today's modern periodic table arranges elements by atomic number (number of protons) and includes Group 0 (noble gases). Remember: atomic number = protons, mass number = protons + neutrons.
Ions are simply charged atoms (gained or lost electrons), whilst isotopes are atoms with different numbers of neutrons but the same number of protons.
Quick Check: Can you explain why isotopes of the same element have the same chemical properties but different masses?
Electron Arrangement and Chemical Behaviour
Here's where atomic structure gets really exciting - electron shells determine how elements behave! The first shell holds up to 2 electrons, whilst the 2nd, 3rd, and 4th shells each hold up to 8 electrons.
The number of electrons in the outer shell is absolutely crucial because it dictates how an element reacts and which group it belongs to in the periodic table. Elements in the same group have the same number of outer shell electrons, which explains why they have similar chemical properties.
This electron arrangement is like a chemical fingerprint - once you know it, you can predict how an element will behave in reactions. It's the key to understanding why sodium and potassium (both Group 1) react similarly with water, or why helium and neon (both Group 0) are so unreactive.
Pro Tip: Draw out electron shell diagrams for the first 20 elements - this visual approach will make predicting chemical behaviour much easier in exams!
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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.
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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
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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
Understanding Atomic Structure - GCSE Chemistry Chapter 1
T
Tara Vidal
@taravidal_jrny
Chemistry might seem complex, but it's really about understanding how matter behaves and changes around us. These fundamental concepts will help you master everything from separating mixtures to understanding atomic structure - skills you'll use throughout your chemistry studies.
Basic Chemistry Concepts and Separation Techniques
Ever wondered how scientists identify what's in your drink or separate oil from water? State symbols are your first clue - they tell you whether something is solid (s), liquid (l), gas (g), or dissolved in water, called aqueous (aq).
The Law of Conservation of Mass is chemistry's golden rule: matter can't be created or destroyed, only rearranged. This means in any chemical reaction, you'll always end up with the same total mass you started with. Understanding the difference between compounds (chemically bonded substances) and mixtures (just mixed together) helps explain why we can separate mixtures using physical methods.
You've got four main separation techniques in your toolkit: filtration for removing insoluble substances, crystallisation for separating dissolved solids from liquids by heating, chromatography for separating multiple solutes, and distillation for separating liquids from solids or liquids with different boiling points.
Key Tip: Remember that simple distillation works by evaporating then condensing, whilst fractional distillation uses different boiling points to separate liquid mixtures - perfect for separating crude oil!
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Atomic Structure and the Periodic Table
Your understanding of atoms started with J.J. Thomson's discovery of electrons and his plum pudding model, which imagined electrons scattered randomly in a positive mass - like raisins in a pudding. However, the famous Gold Leaf Experiment completely changed this picture by firing alpha particles at gold foil.
The results were mind-blowing: most particles passed straight through (atoms are mostly empty space!), some deflected (the centre is positively charged), and some bounced back (the centre contains lots of mass). This proved atoms have a dense, positive nucleus surrounded by mostly empty space.
Mendeleev's periodic table organised elements by increasing atomic weight and cleverly left spaces for undiscovered elements. Today's modern periodic table arranges elements by atomic number (number of protons) and includes Group 0 (noble gases). Remember: atomic number = protons, mass number = protons + neutrons.
Ions are simply charged atoms (gained or lost electrons), whilst isotopes are atoms with different numbers of neutrons but the same number of protons.
Quick Check: Can you explain why isotopes of the same element have the same chemical properties but different masses?
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Electron Arrangement and Chemical Behaviour
Here's where atomic structure gets really exciting - electron shells determine how elements behave! The first shell holds up to 2 electrons, whilst the 2nd, 3rd, and 4th shells each hold up to 8 electrons.
The number of electrons in the outer shell is absolutely crucial because it dictates how an element reacts and which group it belongs to in the periodic table. Elements in the same group have the same number of outer shell electrons, which explains why they have similar chemical properties.
This electron arrangement is like a chemical fingerprint - once you know it, you can predict how an element will behave in reactions. It's the key to understanding why sodium and potassium (both Group 1) react similarly with water, or why helium and neon (both Group 0) are so unreactive.
Pro Tip: Draw out electron shell diagrams for the first 20 elements - this visual approach will make predicting chemical behaviour much easier in exams!
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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