Covalent Bonding
Muhtasari
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.
Malengo
- 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
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Tathmini ya Somo
Hongera kwa kukamilisha somo la Covalent Bonding. Sasa kwa kuwa umechunguza dhana na mawazo muhimu, ni wakati wa kuweka ujuzi wako kwa mtihani. Sehemu hii inatoa mazoezi mbalimbali maswali yaliyoundwa ili kuimarisha uelewaji wako na kukusaidia kupima ufahamu wako wa nyenzo.
Utakutana na mchanganyiko wa aina mbalimbali za maswali, ikiwemo maswali ya kuchagua jibu sahihi, maswali ya majibu mafupi, na maswali ya insha. Kila swali limebuniwa kwa umakini ili kupima vipengele tofauti vya maarifa yako na ujuzi wa kufikiri kwa makini.
Tumia sehemu hii ya tathmini kama fursa ya kuimarisha uelewa wako wa mada na kubaini maeneo yoyote ambapo unaweza kuhitaji kusoma zaidi. Usikatishwe tamaa na changamoto zozote utakazokutana nazo; badala yake, zitazame kama fursa za kukua na kuboresha.
- 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
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Vitabu Vinavyopendekezwa
Jifunze zaidi kutoka vyanzo huria
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Sehemu ya kitabu
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
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Sehemu ya kitabu
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
Vimechapishwa na mashirika mengine chini ya leseni huria na vinatajwa kama wanavyoomba. Viungo hufungua tovuti zao.
Fanya Mazoezi ya Maswali ya Majaribio
Ungependa kufanya mazoezi ya maswali ya majaribio kuhusu Covalent Bonding? Pakua programu ya Green Bridge CBT ili kupata maswali ya majaribio na tathmini kamili za mazoezi kuhusu mada hii.
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