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1l the quest for political stability: germany, 1871-1991
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Chemistry
21 Nov 2025
327
1 page
Alexander Savkovic @alexandersavkovic
The Modern Periodic Table organises elements based on their properties and electron arrangements. It helps us understand why... Show more
The periodic table isn't just a random arrangement of elements - it's designed to show important patterns. Elements in the same group (column) share similar chemical properties because they have the same number of electrons in their outer shell.
Group 1 elements (alkali metals) are soft with low melting points and densities. Some can even float on water! They all have one electron in their outer shell, which they readily lose during reactions. As you go down Group 1, elements become more reactive because the outer electron is farther from the nucleus.
Group 7 elements (halogens) have seven electrons in their outer shell and react by gaining an electron. Unlike Group 1, they become less reactive as you go down the group. Their melting and boiling points increase dramatically down the group - fluorine boils at about -180°C while iodine boils around 180°C!
Remember this! Group 1 elements get MORE reactive going down the group, while Group 7 elements get LESS reactive going down. This pattern is key for your exams!
Electron shells help determine an element's position in the periodic table. Each shell can hold a specific maximum number of electrons (first shell 2, second 8, third 8, fourth 2). Elements fill their shells in order, starting with the shell closest to the nucleus.
While Group 1 and Group 7 have predictable patterns, these don't always help predict how other groups behave. Group 2 metals (like Group 1) have low melting points and reactivity increases down the group, but they're less reactive overall since they have two electrons to lose. Group 0 elements (noble gases) are completely different from Group 7 - they have full outer shells making them extremely unreactive.
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.
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Explore the fundamentals of atomic structure, including key concepts such as atomic models, the periodic table, and the classification of matter. This summary covers J.J. Thomson's discoveries, the Gold Leaf experiment, and the differences between compounds and mixtures. Ideal for GCSE Chemistry students preparing for AQA exams.
ChemistryExplore the reactivity of alkali metals and halogens through displacement reactions and chemical equations. This study note includes practice questions, detailed explanations of periodic trends, and insights into balancing equations. Ideal for exam preparation in chemistry.
ChemistryExplore the fundamentals of atomic structure and the periodic table in this comprehensive summary. Understand electron configurations, atomic particles, and the classification of elements into metals, non-metals, and metalloids. Ideal for chemistry students preparing for exams or seeking to reinforce their knowledge of key concepts in atomic theory and the periodic table.
ChemistryExplore the properties of transition metals, alkali metals, and halogens, including their reactivity trends, atomic structure, and applications. This summary covers key concepts such as metallic bonding, noble gases, and the periodic table organization, making it essential for chemistry students preparing for exams.
ChemistryExplore the properties and trends of Group 1 (Alkali Metals) and Group 7 (Halogens) in the periodic table. This summary covers reactivity patterns, key elements, and the significance of halide ions. Ideal for students preparing for chemistry exams.
ChemistryExplore the properties and reactions of alkali metals, halogens, and noble gases in this detailed summary. Understand the unique characteristics of each group, including their electron configurations, reactivity, and industrial applications. Ideal for GCSE chemistry students looking to grasp key concepts in atomic structure and bonding.
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
Alexander Savkovic
@alexandersavkovic
The Modern Periodic Table organises elements based on their properties and electron arrangements. It helps us understand why elements in the same group behave similarly and how their reactivity changes as you move through the table.
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The periodic table isn't just a random arrangement of elements - it's designed to show important patterns. Elements in the same group (column) share similar chemical properties because they have the same number of electrons in their outer shell.
Group 1 elements (alkali metals) are soft with low melting points and densities. Some can even float on water! They all have one electron in their outer shell, which they readily lose during reactions. As you go down Group 1, elements become more reactive because the outer electron is farther from the nucleus.
Group 7 elements (halogens) have seven electrons in their outer shell and react by gaining an electron. Unlike Group 1, they become less reactive as you go down the group. Their melting and boiling points increase dramatically down the group - fluorine boils at about -180°C while iodine boils around 180°C!
Remember this! Group 1 elements get MORE reactive going down the group, while Group 7 elements get LESS reactive going down. This pattern is key for your exams!
Electron shells help determine an element's position in the periodic table. Each shell can hold a specific maximum number of electrons (first shell: 2, second: 8, third: 8, fourth: 2). Elements fill their shells in order, starting with the shell closest to the nucleus.
While Group 1 and Group 7 have predictable patterns, these don't always help predict how other groups behave. Group 2 metals (like Group 1) have low melting points and reactivity increases down the group, but they're less reactive overall since they have two electrons to lose. Group 0 elements (noble gases) are completely different from Group 7 - they have full outer shells making them extremely unreactive.
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.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the fundamentals of atomic structure, including key concepts such as atomic models, the periodic table, and the classification of matter. This summary covers J.J. Thomson's discoveries, the Gold Leaf experiment, and the differences between compounds and mixtures. Ideal for GCSE Chemistry students preparing for AQA exams.
ChemistryExplore the reactivity of alkali metals and halogens through displacement reactions and chemical equations. This study note includes practice questions, detailed explanations of periodic trends, and insights into balancing equations. Ideal for exam preparation in chemistry.
ChemistryExplore the fundamentals of atomic structure and the periodic table in this comprehensive summary. Understand electron configurations, atomic particles, and the classification of elements into metals, non-metals, and metalloids. Ideal for chemistry students preparing for exams or seeking to reinforce their knowledge of key concepts in atomic theory and the periodic table.
ChemistryExplore the properties of transition metals, alkali metals, and halogens, including their reactivity trends, atomic structure, and applications. This summary covers key concepts such as metallic bonding, noble gases, and the periodic table organization, making it essential for chemistry students preparing for exams.
ChemistryExplore the properties and trends of Group 1 (Alkali Metals) and Group 7 (Halogens) in the periodic table. This summary covers reactivity patterns, key elements, and the significance of halide ions. Ideal for students preparing for chemistry exams.
ChemistryExplore the properties and reactions of alkali metals, halogens, and noble gases in this detailed summary. Understand the unique characteristics of each group, including their electron configurations, reactivity, and industrial applications. Ideal for GCSE chemistry students looking to grasp key concepts in atomic structure and bonding.
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
