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15 Jan 2026
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Shapes of Molecules and Ions: Easy Notes and PDFs
Maya A
@maya.ah
Shapes of Molecules and Molecular Ions
This page provides a comprehensive overview of the shapes of molecules and molecular ions, focusing on the principles that determine their geometries. The document begins by explaining that the shape of a molecule or molecular ion is dependent on the number of electron pairs in the outer shell of the central atom.
The concept of charge clouds is introduced, describing them as areas where electrons are likely to be found. The document then delves into the Valence Shell Electron Pair Repulsion (VSEPR) theory, which is fundamental to understanding molecular shapes.
Definition: A charge cloud is an area where there is a high probability of finding an electron, with electrons moving within this cloud.
The page presents a systematic approach to determining molecular shapes:
- Identify the central atom
- Count the electrons in the outer shell of the central atom
- Add electrons for bonded atoms and account for ionic charges
- Calculate the total number of electron pairs
- Determine the number of lone pairs and bonding pairs
Various molecular geometries are illustrated, including:
- Linear (2 electron pairs)
- Trigonal planar (3 electron pairs)
- Tetrahedral (4 electron pairs)
- Trigonal pyramidal (4 electron pairs, 1 lone pair)
- Bent or V-shaped (4 electron pairs, 2 lone pairs)
- Trigonal bipyramidal (5 electron pairs)
- See-saw (5 electron pairs, 1 lone pair)
- T-shaped (5 electron pairs, 2 lone pairs)
- Octahedral (6 electron pairs)
- Square pyramidal (6 electron pairs, 1 lone pair)
- Square planar (6 electron pairs, 2 lone pairs)
Highlight: The VSEPR theory explains that electrons, being negatively charged, repel each other, resulting in electron pairs positioning themselves at the greatest possible distance from one another.
Example: Ammonia (NH₃) has a trigonal pyramidal shape with a bond angle of 107°, due to the presence of three bonding pairs and one lone pair on the nitrogen atom.
The document also notes the importance of understanding bond angles, which vary depending on the molecular geometry and the presence of lone pairs. For instance, the bond angle in a linear molecule is 180°, while in a tetrahedral molecule it's 109.5°.
Vocabulary: Bonding pairs refer to shared electrons between atoms, while lone pairs are unshared electrons on the central atom.
This comprehensive guide serves as an excellent resource for students studying molecular shapes in A-level Chemistry or those seeking to understand the VSEPR theory for B.Sc. first year courses.
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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.
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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
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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
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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 Knowunity AI. 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
Shapes of Molecules and Ions: Easy Notes and PDFs
Maya A
@maya.ah
The shapes of molecules and molecular ions are determined by the arrangement of electron pairs around the central atom. This arrangement is influenced by the Valence Shell Electron Pair Repulsion (VSEPR) theory, which states that electron pairs repel each... Show more
Shapes of Molecules and Molecular Ions
This page provides a comprehensive overview of the shapes of molecules and molecular ions, focusing on the principles that determine their geometries. The document begins by explaining that the shape of a molecule or molecular ion is dependent on the number of electron pairs in the outer shell of the central atom.
The concept of charge clouds is introduced, describing them as areas where electrons are likely to be found. The document then delves into the Valence Shell Electron Pair Repulsion (VSEPR) theory, which is fundamental to understanding molecular shapes.
Definition: A charge cloud is an area where there is a high probability of finding an electron, with electrons moving within this cloud.
The page presents a systematic approach to determining molecular shapes:
- Identify the central atom
- Count the electrons in the outer shell of the central atom
- Add electrons for bonded atoms and account for ionic charges
- Calculate the total number of electron pairs
- Determine the number of lone pairs and bonding pairs
Various molecular geometries are illustrated, including:
- Linear (2 electron pairs)
- Trigonal planar (3 electron pairs)
- Tetrahedral (4 electron pairs)
- Trigonal pyramidal (4 electron pairs, 1 lone pair)
- Bent or V-shaped (4 electron pairs, 2 lone pairs)
- Trigonal bipyramidal (5 electron pairs)
- See-saw (5 electron pairs, 1 lone pair)
- T-shaped (5 electron pairs, 2 lone pairs)
- Octahedral (6 electron pairs)
- Square pyramidal (6 electron pairs, 1 lone pair)
- Square planar (6 electron pairs, 2 lone pairs)
Highlight: The VSEPR theory explains that electrons, being negatively charged, repel each other, resulting in electron pairs positioning themselves at the greatest possible distance from one another.
Example: Ammonia (NH₃) has a trigonal pyramidal shape with a bond angle of 107°, due to the presence of three bonding pairs and one lone pair on the nitrogen atom.
The document also notes the importance of understanding bond angles, which vary depending on the molecular geometry and the presence of lone pairs. For instance, the bond angle in a linear molecule is 180°, while in a tetrahedral molecule it's 109.5°.
Vocabulary: Bonding pairs refer to shared electrons between atoms, while lone pairs are unshared electrons on the central atom.
This comprehensive guide serves as an excellent resource for students studying molecular shapes in A-level Chemistry or those seeking to understand the VSEPR theory for B.Sc. first year courses.
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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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 Knowunity AI. 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 Knowunity AI. 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