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Sophia + Charlotte
01/07/2023
Chemistry
Atomic structure and the periodic table
3,618
•
1 Jul 2023
•
How to Calculate Relative Atomic Mass and Differences Between Ionic and Covalent Bonds - Easy Steps and Examples
Separation Techniques
This page delves deeper into various separation techniques used in chemistry:
-
Filtration: Separates insoluble solids from liquids using filter paper.
-
Evaporation: Separates soluble solids from solutions by heating and evaporating the liquid.
-
Simple distillation: Used to separate a liquid from a solution.
Highlight: In simple distillation, the solution is heated, and the component with the lowest boiling point evaporates first, is cooled, and then collected.
- Fractional distillation: Used to separate mixtures of liquids with different boiling points.
Example: In fractional distillation of crude oil, different components are separated based on their boiling points, with lighter fractions like gasoline collected first, followed by heavier fractions like diesel and lubricating oils.
The page provides detailed distillation procedure step-by-step instructions for both simple and fractional distillation, making it an excellent resource for students learning about simple distillation separation technique steps.
History of Atomic Models
This page traces the evolution of atomic models throughout history:
-
Early 19th century: John Dalton's "Billiard Ball Model" - atoms as solid spheres
-
1897: J.J. Thomson's "Plum Pudding Model" - atoms as positively charged balls with embedded negative electrons
-
1909: Ernest Rutherford's "Nuclear Model" - atoms with a small, dense, positively charged nucleus surrounded by electrons
-
Niels Bohr's Nuclear Model - electrons orbiting the nucleus in fixed shells
Highlight: Rutherford's alpha particle scattering experiment provided crucial evidence for the nuclear model of the atom.
Example: In Rutherford's experiment, most alpha particles passed through a thin gold foil, but some were deflected at large angles, indicating a small, dense nucleus.
The page also mentions James Chadwick's discovery of neutrons about 20 years after Rutherford's model.
Development of the Periodic Table
This final page discusses the evolution of the periodic table:
- Initially, elements were ordered solely by atomic weight
- In 1869, Dmitri Mendeleev introduced a new approach to organizing elements
Highlight: Mendeleev's periodic table overcame some of the problems associated with earlier arrangements of elements.
The page emphasizes the importance of Mendeleev's work in the development of the modern periodic table, which is a crucial tool for understanding elemental properties and chemical behavior.
This section provides a historical context for the organization of elements, helping students appreciate the scientific process that led to our current understanding of atomic structure and elemental relationships.
Atomic Structure and the Periodic Table
This page introduces key concepts in atomic structure and the periodic table, including:
- Subatomic particles (protons, neutrons, electrons) and their properties
- Atomic structure notation
- Definition of elements, isotopes, and compounds
- Types of chemical bonding (ionic and covalent)
- Mixtures and separation techniques
Vocabulary: An element is a substance made up of one type of atom.
Definition: Isotopes are different forms of an element with the same number of protons but different numbers of neutrons.
Example: Sodium (Na) has an atomic number of 11 and a mass number of 23.
The page also covers how to calculate relative atomic mass of isotopes using the following formula:
Relative atomic mass = Sum of (isotope mass x isotope abundance) / Sum of abundances of all isotopes
Highlight: Chemical compounds are formed from two or more elements held together by chemical bonds.
The page concludes with an overview of separation techniques, focusing on chromatography:
- Draw a pencil line on filter paper
- Add a spot of ink to the line
- Place the paper in a beaker with solvent
- Allow the solvent to travel up the paper, separating the ink components
Vocabulary: The Rf value is calculated as the distance traveled by the compound divided by the distance traveled by the solvent.
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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
How to Calculate Relative Atomic Mass and Differences Between Ionic and Covalent Bonds - Easy Steps and Examples
The atomic structure and periodic table are fundamental concepts in chemistry, covering atoms, elements, compounds, and separation techniques. This guide explores atomic particles, isotopes, chemical bonding, and the historical development of atomic models and the periodic table.
Separation Techniques
This page delves deeper into various separation techniques used in chemistry:
-
Filtration: Separates insoluble solids from liquids using filter paper.
-
Evaporation: Separates soluble solids from solutions by heating and evaporating the liquid.
-
Simple distillation: Used to separate a liquid from a solution.
Highlight: In simple distillation, the solution is heated, and the component with the lowest boiling point evaporates first, is cooled, and then collected.
- Fractional distillation: Used to separate mixtures of liquids with different boiling points.
Example: In fractional distillation of crude oil, different components are separated based on their boiling points, with lighter fractions like gasoline collected first, followed by heavier fractions like diesel and lubricating oils.
The page provides detailed distillation procedure step-by-step instructions for both simple and fractional distillation, making it an excellent resource for students learning about simple distillation separation technique steps.
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
History of Atomic Models
This page traces the evolution of atomic models throughout history:
-
Early 19th century: John Dalton's "Billiard Ball Model" - atoms as solid spheres
-
1897: J.J. Thomson's "Plum Pudding Model" - atoms as positively charged balls with embedded negative electrons
-
1909: Ernest Rutherford's "Nuclear Model" - atoms with a small, dense, positively charged nucleus surrounded by electrons
-
Niels Bohr's Nuclear Model - electrons orbiting the nucleus in fixed shells
Highlight: Rutherford's alpha particle scattering experiment provided crucial evidence for the nuclear model of the atom.
Example: In Rutherford's experiment, most alpha particles passed through a thin gold foil, but some were deflected at large angles, indicating a small, dense nucleus.
The page also mentions James Chadwick's discovery of neutrons about 20 years after Rutherford's model.
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
Development of the Periodic Table
This final page discusses the evolution of the periodic table:
- Initially, elements were ordered solely by atomic weight
- In 1869, Dmitri Mendeleev introduced a new approach to organizing elements
Highlight: Mendeleev's periodic table overcame some of the problems associated with earlier arrangements of elements.
The page emphasizes the importance of Mendeleev's work in the development of the modern periodic table, which is a crucial tool for understanding elemental properties and chemical behavior.
This section provides a historical context for the organization of elements, helping students appreciate the scientific process that led to our current understanding of atomic structure and elemental relationships.
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
Atomic Structure and the Periodic Table
This page introduces key concepts in atomic structure and the periodic table, including:
- Subatomic particles (protons, neutrons, electrons) and their properties
- Atomic structure notation
- Definition of elements, isotopes, and compounds
- Types of chemical bonding (ionic and covalent)
- Mixtures and separation techniques
Vocabulary: An element is a substance made up of one type of atom.
Definition: Isotopes are different forms of an element with the same number of protons but different numbers of neutrons.
Example: Sodium (Na) has an atomic number of 11 and a mass number of 23.
The page also covers how to calculate relative atomic mass of isotopes using the following formula:
Relative atomic mass = Sum of (isotope mass x isotope abundance) / Sum of abundances of all isotopes
Highlight: Chemical compounds are formed from two or more elements held together by chemical bonds.
The page concludes with an overview of separation techniques, focusing on chromatography:
- Draw a pencil line on filter paper
- Add a spot of ink to the line
- Place the paper in a beaker with solvent
- Allow the solvent to travel up the paper, separating the ink components
Vocabulary: The Rf value is calculated as the distance traveled by the compound divided by the distance traveled by the solvent.
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?
You can download the app from Google Play Store and Apple App Store.
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.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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