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AP Chemistry
Dec 11, 2025
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Lewis Structures help us visualize how atoms share electrons in molecules. They show us how valence electrons are... Show more
Lewis Structures are like molecular blueprints that show how valence electrons arrange themselves around atoms in covalently bonded molecules. They reveal which electrons are being shared between atoms and which ones remain as lone pairs. Remember though - these structures don't show the actual 3D shape of molecules!
In these diagrams, we represent single bonds with one line (sharing 2 electrons), double bonds with two lines (sharing 4 electrons), and triple bonds with three lines (sharing 6 electrons). For example, methane (CH₄) shows carbon with four single bonds to hydrogen atoms, while nitrogen gas (N₂) shows a triple bond between nitrogen atoms.
When drawing atoms, we can show lone pairs (unshared electrons) as dots. Sulfur might have dots representing its lone pairs, while oxygen in a double bond would share 4 electrons with another atom while keeping some electrons to itself.
Quick Tip Valence electrons come from the outermost s and p orbitals, which is why most atoms can have up to 8 valence electrons (octet).
The famous Octet Rule tells us that atoms generally want 8 valence electrons to be stable (except hydrogen, which wants 2). When looking at a Lewis structure, check if each atom has access to 8 electrons either through sharing or as lone pairs.
To draw a Lewis Structure, first identify the central atom - usually it's the least electronegative atom, the one written first in the formula, or the "different" atom. For example, in NH₃, nitrogen is central while the hydrogens surround it.
Next, count the total available electrons by adding up all valence electrons from each atom. For NH₃, nitrogen contributes 5 electrons and each hydrogen contributes 1, giving a total of 8 valence electrons to work with.
Remember The rules for Lewis Structures are more like guidelines than absolute rules. Some exceptions exist, especially for larger atoms!
After counting available electrons, determine how many electrons each atom needs for a complete octet. For NH₃, nitrogen needs 8 electrons and each hydrogen needs 2, totaling 14 electrons needed.
Calculate how many bonds to draw by subtracting available electrons from needed electrons and dividing by 2. For NH₃ (14-8)/2 = 3 bonds. Draw these bonds connecting your atoms.
Finally, add lone pairs to any atoms that still need electrons to complete their octets. In NH₃, after drawing three N-H bonds, nitrogen still needs a lone pair to reach its octet.
Pro Tip Always double-check your work by counting electrons in your final structure - the total should match what you calculated in step 3!
Sometimes molecules break the octet rule, especially with larger atoms like sulfur (SF₆) or xenon (XeF₄). These atoms can access d orbitals, allowing them to accommodate more than 8 electrons.
Formal charge helps verify if your Lewis structure makes sense. Calculate it by subtracting the number of electrons "owned" by an atom from its normal valence electrons. Ideally, formal charges should be zero or as close to zero as possible.
When drawing multiple possible structures, choose the one where formal charges are minimized and distributed evenly. It's better to have two -1 charges than one -2 charge in your structure.
Important When working with polyatomic ions like CO₃²⁻, remember to add or subtract electrons based on the overall charge of the molecule!
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
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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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Learning one of the foundation skills in chemistry: balancing chemical equations.
ChemistryThe Lewis Dot Structure of Elements of the Periodic Table
ChemistryThis is about recognizing and naming Binary Ionic Compound
ChemistryExplore the fundamental concepts of chemistry, including states of matter, classification of elements, atomic structure, the Periodic Table, chemical bonding (ionic, covalent, metallic), and electrolysis. This comprehensive summary is essential for mastering key principles in chemistry.
Chemistry2 questions each with 2 sub-questions. The questions are solved with the correct solutions
AP 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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Lewis Structures help us visualize how atoms share electrons in molecules. They show us how valence electrons are arranged and how atoms connect to each other through chemical bonds, giving us a paper representation of covalent bonding.
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Lewis Structures are like molecular blueprints that show how valence electrons arrange themselves around atoms in covalently bonded molecules. They reveal which electrons are being shared between atoms and which ones remain as lone pairs. Remember though - these structures don't show the actual 3D shape of molecules!
In these diagrams, we represent single bonds with one line (sharing 2 electrons), double bonds with two lines (sharing 4 electrons), and triple bonds with three lines (sharing 6 electrons). For example, methane (CH₄) shows carbon with four single bonds to hydrogen atoms, while nitrogen gas (N₂) shows a triple bond between nitrogen atoms.
When drawing atoms, we can show lone pairs (unshared electrons) as dots. Sulfur might have dots representing its lone pairs, while oxygen in a double bond would share 4 electrons with another atom while keeping some electrons to itself.
Quick Tip: Valence electrons come from the outermost s and p orbitals, which is why most atoms can have up to 8 valence electrons (octet).
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The famous Octet Rule tells us that atoms generally want 8 valence electrons to be stable (except hydrogen, which wants 2). When looking at a Lewis structure, check if each atom has access to 8 electrons either through sharing or as lone pairs.
To draw a Lewis Structure, first identify the central atom - usually it's the least electronegative atom, the one written first in the formula, or the "different" atom. For example, in NH₃, nitrogen is central while the hydrogens surround it.
Next, count the total available electrons by adding up all valence electrons from each atom. For NH₃, nitrogen contributes 5 electrons and each hydrogen contributes 1, giving a total of 8 valence electrons to work with.
Remember: The rules for Lewis Structures are more like guidelines than absolute rules. Some exceptions exist, especially for larger atoms!
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Improve your grades
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After counting available electrons, determine how many electrons each atom needs for a complete octet. For NH₃, nitrogen needs 8 electrons and each hydrogen needs 2, totaling 14 electrons needed.
Calculate how many bonds to draw by subtracting available electrons from needed electrons and dividing by 2. For NH₃: (14-8)/2 = 3 bonds. Draw these bonds connecting your atoms.
Finally, add lone pairs to any atoms that still need electrons to complete their octets. In NH₃, after drawing three N-H bonds, nitrogen still needs a lone pair to reach its octet.
Pro Tip: Always double-check your work by counting electrons in your final structure - the total should match what you calculated in step 3!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Sometimes molecules break the octet rule, especially with larger atoms like sulfur (SF₆) or xenon (XeF₄). These atoms can access d orbitals, allowing them to accommodate more than 8 electrons.
Formal charge helps verify if your Lewis structure makes sense. Calculate it by subtracting the number of electrons "owned" by an atom from its normal valence electrons. Ideally, formal charges should be zero or as close to zero as possible.
When drawing multiple possible structures, choose the one where formal charges are minimized and distributed evenly. It's better to have two -1 charges than one -2 charge in your structure.
Important: When working with polyatomic ions like CO₃²⁻, remember to add or subtract electrons based on the overall charge of the molecule!
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Learning one of the foundation skills in chemistry: balancing chemical equations.
ChemistryThe Lewis Dot Structure of Elements of the Periodic Table
ChemistryThis is about recognizing and naming Binary Ionic Compound
ChemistryExplore the fundamental concepts of chemistry, including states of matter, classification of elements, atomic structure, the Periodic Table, chemical bonding (ionic, covalent, metallic), and electrolysis. This comprehensive summary is essential for mastering key principles in chemistry.
Chemistry2 questions each with 2 sub-questions. The questions are solved with the correct solutions
AP 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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
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