Covalent Bonding
Visão Geral
Water, oxygen, carbon dioxide, plastics, diamond - all of these substances are held together by covalent bonds, yet their physical properties could not be more different. The key lies in whether the covalent bonds build small, individual molecules or extend into giant lattices that stretch in every direction.
This lesson explains how atoms share electron pairs to form covalent bonds, how to draw dot-and-cross diagrams for a range of molecules, and why simple molecular substances have low melting points while giant covalent structures like diamond are among the hardest materials on Earth. You will also explore graphite and C60 fullerene and learn to link structure to properties.
Objetivos
- know that a covalent bond is formed between atoms by the sharing of a pair of electrons
- understand covalent bonds in terms of electrostatic attractions
- understand how to use dot-and-cross diagrams to represent covalent bonds in:
- • diatomic molecules, including hydrogen, oxygen, nitrogen, halogens and hydrogen halides - inorganic molecules including water, ammonia and carbon dioxide - organic molecules containing up to two carbon atoms, including methane, ethane, ethene and those containing halogen atoms. explain why substances with a simple molecular structures are gases or liquids, or solids with low melting and boiling points the term intermolecular forces of attraction can be used to represent all forces between molecules
- explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass
- explain why substances with giant covalent structures are solids with high melting and boiling points
- explain how the structures of diamond, graphite and C60 fullerene influence their physical properties, including electrical conductivity and hardness
- know that covalent compounds do not usually conduct electricity
Mapa mental
Este tema esta mapeado para mostrar como as ideias se ligam.
Abra o mapa mental na aplicacao
Cartoes
Pratica rapida de memoria sobre o que e avaliado neste tema.
Pratique estes cartoes na aplicacao
Nota de Aula
Apontamento completo disponivel na aplicacao Green Bridge
Instale a aplicacao Green Bridge CBT no telemovel ou computador para aceder a biblioteca IGCSE completa: exames anteriores, criterios de correcao, mapas mentais, cartoes de estudo e licoes em audio.
Avaliação da Lição
Parabéns por concluir a lição em Covalent Bonding. Agora que você explorou o conceitos e ideias-chave, é hora de colocar seu conhecimento à prova. Esta seção oferece uma variedade de práticas perguntas destinadas a reforçar sua compreensão e ajudá-lo a avaliar sua compreensão do material.
Irá encontrar uma mistura de tipos de perguntas, incluindo perguntas de escolha múltipla, perguntas de resposta curta e perguntas de redação. Cada pergunta é cuidadosamente elaborada para avaliar diferentes aspetos do seu conhecimento e competências de pensamento crítico.
Use esta secção de avaliação como uma oportunidade para reforçar a tua compreensão do tema e identificar quaisquer áreas onde possas precisar de estudo adicional. Não te deixes desencorajar pelos desafios que encontrares; em vez disso, vê-os como oportunidades de crescimento e melhoria.
- How many bonding pairs of electrons are in a molecule of water, H2O? A) 1 B) 2 C) 3 D) 4 Answer: B
- Which of these substances has a giant covalent structure? A) Carbon dioxide B) Water C) Diamond D) Sodium chloride Answer: C
- Why does graphite conduct electricity? A) It contains ions that are free to move B) It contains delocalised electrons that can move along the layers C) It has a low melting point D) Its covalent bonds carry charge Answer: B
- Simple molecular substances have low boiling points because: A) Their covalent bonds are weak B) Their intermolecular forces are weak C) They contain ions D) They have giant structures Answer: B
- How many carbon atoms are in one molecule of buckminsterfullerene? A) 12 B) 24 C) 60 D) 120 Answer: C
Resolva estas questoes na aplicacao
Resolva estas questoes na aplicacao
Livros Recomendados
Para aprender mais, fontes abertas
-
Secção do manual
Lewis Symbols and Structures
Write Lewis symbols for neutral atoms and ions
"Chemistry: Lewis Symbols and Structures" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/chemistry/pages/7-3-lewis-symbols-and-structures. Access for free at https://openstax.org/books/chemistry/pages/1-introduction
-
Secção do manual
The Solid State of Matter
Define and describe the bonding and properties of ionic, molecular, metallic, and covalent network crystalline solids
"Chemistry: The Solid State of Matter" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/chemistry/pages/10-5-the-solid-state-of-matter. Access for free at https://openstax.org/books/chemistry/pages/1-introduction
Publicados por outras organizações com licenças abertas e creditados como pedem. As ligações abrem os seus sites.
Pratique Questões Simuladas
Quer praticar questões simuladas sobre Covalent Bonding? Descarregue a aplicação Green Bridge CBT para aceder a questões simuladas e avaliações completas sobre este tópico.
Descarregar a aplicação na Google Play Store
Tudo o que precisas para te destacares no JAMB, WAEC e NECO.
