Subjects
Classic Dramatic Literature
Modern Lyric Poetry
Influential English-Language Authors
Classic and Contemporary Novels
Literary Character Analysis
Romantic and Love Poetry
Reading Analysis and Interpretation
Evidence Analysis and Integration
Author's Stylistic Elements
Figurative Language and Rhetoric
Show all topics
Human Organ Systems
Cellular Organization and Development
Biomolecular Structure and Organization
Enzyme Structure and Regulation
Cellular Organization Types
Biological Homeostatic Processes
Cellular Membrane Structure
Autotrophic Energy Processes
Environmental Sustainability and Impact
Neural Communication Systems
Show all topics
Social Sciences Research & Practice
Social Structure and Mobility
Classic Social Influence Experiments
Social Systems Theories
Family and Relationship Dynamics
Memory Systems and Processes
Neural Bases of Behavior
Social Influence and Attraction
Psychotherapeutic Approaches
Human Agency and Responsibility
Show all topics
Chemical Sciences and Applications
Chemical Bond Types and Properties
Organic Functional Groups
Atomic Structure and Composition
Chromatographic Separation Principles
Chemical Compound Classifications
Electrochemical Cell Systems
Periodic Table Organization
Chemical Reaction Kinetics
Chemical Equation Conservation
Show all topics
Nazi Germany and Holocaust 1933-1945
World Wars and Peace Treaties
European Monarchs and Statesmen
Cold War Global Tensions
Medieval Institutions and Systems
European Renaissance and Enlightenment
Modern Global Environmental-Health Challenges
Modern Military Conflicts
Medieval Migration and Invasions
World Wars Era and Impact
Show all topics
499
•
21 Dec 2025
•
hikma
@h1kmar
Understanding how atoms bond together is absolutely crucial for chemistry... Show more
Ever wondered why some substances conduct electricity whilst others don't? It all comes down to chemical bonding - how atoms stick together to become more stable by achieving full outer electron shells.
There are three main ways atoms can bond: ionic bonding , covalent bonding , and metallic bonding (metals with delocalised electrons). Each type creates completely different properties in the resulting compounds.
Ionic bonding happens when metals (groups 1 & 2) meet non-metals (groups 6 & 7). The metal atoms lose electrons to become positive ions (cations), whilst non-metals gain those electrons to become negative ions (anions). These oppositely charged ions attract each other through strong electrostatic forces - that's your ionic bond.
Quick tip: Group 1 metals form 1+ ions, group 2 form 2+ ions. Group 6 non-metals form 2- ions, group 7 form 1- ions. This pattern makes predicting ionic compounds much easier!
Ionic compounds form massive structures called giant ionic lattices where ions pack together tightly. These have sky-high melting and boiling points because breaking all those strong electrostatic attractions requires enormous energy. They're brilliant electrical conductors when liquid but useless when solid.
You can represent these structures in three ways: dot & cross diagrams (show electron origins), displayed formulae (show connections), and ball & stick models (show 3D arrangement). Each method has trade-offs between showing electron movement and spatial arrangement.
Covalent bonding occurs when non-metals share electron pairs rather than transferring them completely. The positive nuclei attract the shared electrons, creating strong bonds. Simple molecular substances like water (H₂O) and methane (CH₄) have strong covalent bonds within molecules but weak forces between molecules.
Remember: Simple molecular substances have low melting points because you're only breaking weak intermolecular forces, not the strong covalent bonds themselves.
Metallic bonding creates some of the most useful materials on Earth. Metal atoms release their outer electrons into a "sea" of delocalised electrons that can move freely. This creates strong electrostatic attraction between positive metal ions and negative electrons, explaining why metals are solid at room temperature with high melting points.
The delocalised electrons make metals excellent electrical conductors and give them malleability - they can be shaped without breaking. Pure metals are often too soft for practical use, so we create alloys by mixing metals with other elements. These are much harder because the different-sized atoms disrupt the regular layers.
The three states of matter depend entirely on particle forces and energy. In solids, strong forces lock particles in fixed positions. Liquids have weaker forces allowing movement whilst staying close together. Gases have very weak forces letting particles move completely freely.
State symbols made simple: (s) = solid, (l) = liquid, (g) = gas, (aq) = dissolved in water. Temperature compared to melting/boiling points tells you which state to expect.
Understanding structure-property relationships is your key to predicting how materials behave. Ionic compounds need loads of energy to melt because you're breaking countless strong electrostatic attractions in their giant lattice structures.
Simple molecular substances like oxygen (O₂) and hydrogen chloride (HCl) have completely opposite properties - low melting points and no electrical conductivity because they're uncharged molecules held together by weak intermolecular forces.
Polymers occupy the middle ground - they're long chains of repeating units (monomers) connected by covalent bonds. The intermolecular forces are stronger than simple molecules but weaker than ionic compounds, making them solid at room temperature but with relatively low melting points.
Polymer insight: Think of polymers like chains - the covalent bonds are strong links, but the forces between different chains are much weaker. This explains their flexibility and moderate melting points.
Giant covalent structures are absolutely massive molecules where every atom connects through covalent bonds. They're incredibly strong with high melting points because breaking them means snapping countless covalent bonds - no weak intermolecular forces to exploit.
Diamond represents the ultimate in hardness because each carbon atom forms four covalent bonds in a rigid 3D network. No delocalised electrons means no electrical conductivity, but the structure makes it perfect for cutting tools.
Graphite shows how structure changes everything - carbon atoms form only three bonds, creating hexagonal layers that can slide over each other. This makes graphite soft and slippery (great for pencils and lubricants), whilst the fourth electron becomes delocalised, allowing electrical conductivity.
Carbon versatility: Same element, completely different properties! Diamond's 3D network vs graphite's layered structure perfectly demonstrates how bonding arrangement controls material behaviour.
Graphene takes graphite's concept to the extreme - it's essentially a single layer of graphite that's one atom thick. This creates an incredibly strong yet lightweight 2D material with excellent electrical conductivity thanks to delocalised electrons.
Fullerenes represent carbon's most creative side, forming closed cages, tubes, or hollow spheres. Buckminsterfullerene was the first discovered - a football-shaped molecule with 60 carbon atoms arranged in hexagons and pentagons.
These structures have exciting applications: fullerenes can deliver drugs by acting as molecular cages, their large surface areas make them brilliant industrial catalysts, and they form nanotubes - tiny carbon cylinders with incredible strength and conductivity. Nanotubes are revolutionising electronics and creating super-strong, lightweight composite materials.
Future materials: Fullerenes and nanotubes represent cutting-edge nanotechnology - their unique properties are opening up possibilities from targeted medical treatments to space-age materials.
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.
App 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
hikma
@h1kmar
Understanding how atoms bond together is absolutely crucial for chemistry success - it explains everything from why salt dissolves in water to how diamonds are so incredibly strong. This topic covers the three main types of chemical bonding and how... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered why some substances conduct electricity whilst others don't? It all comes down to chemical bonding - how atoms stick together to become more stable by achieving full outer electron shells.
There are three main ways atoms can bond: ionic bonding , covalent bonding , and metallic bonding (metals with delocalised electrons). Each type creates completely different properties in the resulting compounds.
Ionic bonding happens when metals (groups 1 & 2) meet non-metals (groups 6 & 7). The metal atoms lose electrons to become positive ions (cations), whilst non-metals gain those electrons to become negative ions (anions). These oppositely charged ions attract each other through strong electrostatic forces - that's your ionic bond.
Quick tip: Group 1 metals form 1+ ions, group 2 form 2+ ions. Group 6 non-metals form 2- ions, group 7 form 1- ions. This pattern makes predicting ionic compounds much easier!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ionic compounds form massive structures called giant ionic lattices where ions pack together tightly. These have sky-high melting and boiling points because breaking all those strong electrostatic attractions requires enormous energy. They're brilliant electrical conductors when liquid but useless when solid.
You can represent these structures in three ways: dot & cross diagrams (show electron origins), displayed formulae (show connections), and ball & stick models (show 3D arrangement). Each method has trade-offs between showing electron movement and spatial arrangement.
Covalent bonding occurs when non-metals share electron pairs rather than transferring them completely. The positive nuclei attract the shared electrons, creating strong bonds. Simple molecular substances like water (H₂O) and methane (CH₄) have strong covalent bonds within molecules but weak forces between molecules.
Remember: Simple molecular substances have low melting points because you're only breaking weak intermolecular forces, not the strong covalent bonds themselves.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Metallic bonding creates some of the most useful materials on Earth. Metal atoms release their outer electrons into a "sea" of delocalised electrons that can move freely. This creates strong electrostatic attraction between positive metal ions and negative electrons, explaining why metals are solid at room temperature with high melting points.
The delocalised electrons make metals excellent electrical conductors and give them malleability - they can be shaped without breaking. Pure metals are often too soft for practical use, so we create alloys by mixing metals with other elements. These are much harder because the different-sized atoms disrupt the regular layers.
The three states of matter depend entirely on particle forces and energy. In solids, strong forces lock particles in fixed positions. Liquids have weaker forces allowing movement whilst staying close together. Gases have very weak forces letting particles move completely freely.
State symbols made simple: (s) = solid, (l) = liquid, (g) = gas, (aq) = dissolved in water. Temperature compared to melting/boiling points tells you which state to expect.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Understanding structure-property relationships is your key to predicting how materials behave. Ionic compounds need loads of energy to melt because you're breaking countless strong electrostatic attractions in their giant lattice structures.
Simple molecular substances like oxygen (O₂) and hydrogen chloride (HCl) have completely opposite properties - low melting points and no electrical conductivity because they're uncharged molecules held together by weak intermolecular forces.
Polymers occupy the middle ground - they're long chains of repeating units (monomers) connected by covalent bonds. The intermolecular forces are stronger than simple molecules but weaker than ionic compounds, making them solid at room temperature but with relatively low melting points.
Polymer insight: Think of polymers like chains - the covalent bonds are strong links, but the forces between different chains are much weaker. This explains their flexibility and moderate melting points.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Giant covalent structures are absolutely massive molecules where every atom connects through covalent bonds. They're incredibly strong with high melting points because breaking them means snapping countless covalent bonds - no weak intermolecular forces to exploit.
Diamond represents the ultimate in hardness because each carbon atom forms four covalent bonds in a rigid 3D network. No delocalised electrons means no electrical conductivity, but the structure makes it perfect for cutting tools.
Graphite shows how structure changes everything - carbon atoms form only three bonds, creating hexagonal layers that can slide over each other. This makes graphite soft and slippery (great for pencils and lubricants), whilst the fourth electron becomes delocalised, allowing electrical conductivity.
Carbon versatility: Same element, completely different properties! Diamond's 3D network vs graphite's layered structure perfectly demonstrates how bonding arrangement controls material behaviour.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Graphene takes graphite's concept to the extreme - it's essentially a single layer of graphite that's one atom thick. This creates an incredibly strong yet lightweight 2D material with excellent electrical conductivity thanks to delocalised electrons.
Fullerenes represent carbon's most creative side, forming closed cages, tubes, or hollow spheres. Buckminsterfullerene was the first discovered - a football-shaped molecule with 60 carbon atoms arranged in hexagons and pentagons.
These structures have exciting applications: fullerenes can deliver drugs by acting as molecular cages, their large surface areas make them brilliant industrial catalysts, and they form nanotubes - tiny carbon cylinders with incredible strength and conductivity. Nanotubes are revolutionising electronics and creating super-strong, lightweight composite materials.
Future materials: Fullerenes and nanotubes represent cutting-edge nanotechnology - their unique properties are opening up possibilities from targeted medical treatments to space-age materials.
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.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Comprehensive resource for Year 12 students pursuing a Level 3 Diploma in Applied Science. This booklet covers essential topics including cell structure, chemical properties, and wave theory, providing clear explanations and key concepts to aid in your studies and exam preparation.
ChemistryBonding
ChemistryExplore key concepts in oxidation and reduction, chemical bonding, and periodic trends. This summary covers reducing and oxidizing agents, intermolecular forces, and stoichiometry, providing essential insights for understanding chemical reactions and molecular structures.
ChemistryExplore the principles of electrolysis, including redox reactions, half-reactions, and the roles of anodes and cathodes. This summary covers key concepts such as electrolytic cells, Faraday's laws, and the significance of electrolytes in conducting electricity. Ideal for students preparing for exams or seeking a clear understanding of electrolysis processes.
ChemistryExplore the key concepts of metallic, ionic, and covalent bonding, including their structures, properties, and the effects of intermolecular forces. This summary covers the principles of bonding types, crystal structures, and the VSEPR theory, providing essential insights for AQA A Level Chemistry students. Ideal for exam preparation and understanding material properties.
ChemistryComprehensive A Level Chemistry summary covering key concepts of bonding types, molecular shapes, electronegativity, and intermolecular forces. Understand ionic, covalent, and dative bonds, along with their properties and effects on molecular behavior. Ideal for exam preparation and revision.
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
English Literature
Biology
Sociology