Covalent Bonding 2.0 / 5 based on 1 rating ? ChemistryStructure and bondingGCSEAQA Created by: Pixie~Flirt (:Created on: 10-10-12 20:44 Covalent Compounds: bonding and properties formed when 2 atoms share electrons, so each achieves full outer shell - stable strong, holding atoms together, simple molecules like hydrogen, chlorine, oxygen etc bonding within molecules are strong whereas forces of attraction between molecules are weak many covalently bonded simple molecules are gases 1 of 3 Simple Molecules consist of small number of atoms held together by pairs of electrons, forming covalent bonds covalent bonds join atoms in simple molecules either gases, solids or liquids with relatively low melting and boiling points don't conduct electricity, no overall electrical charge elements: hydrogen, oxygen and chlorine compounds: water, hydrogen chloride, methane and ammonia within is strong, between is weak, when simple molecule either boils or melts, these intermolecular forces that it overcomes fragrant substances covalently bonded evaporate easily (volatile) in perfumes, substances dissolved in solvents, ethanol, more volatile on skin, solvent evaporates quickly, fragrant molecules evaporate gradually 2 of 3 Giant Covalent Structures very strong covalent bonds, join many atoms arranged in 3D Lattice forming macromolecules high melting points, hard don't conduct electricity or dissolve in water diamond and graphite, 2 forms of carbon - giant covalent structures diamond: covalent bonds join each carbon to 4 others, making - hardest known natural mineral graphite: each carbon atoms bond to 3 others, forming layers - easily slide over each other, soft and slippery, used as lubricant 1 electron form each carbon atom is delocalised, these electrons enable graphite to conduct electricity and heat silicon dioxide: is silica (sand) strong silicon-oxygen covalent bonds in giant structure, very hard high melting point 3 of 3
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