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Published byJulius Stanley Modified over 8 years ago
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5.1- Compounds and Molecules I can: -explain atoms may be bonded together by losing, gaining or sharing electrons to form molecules or three-dimensional lattices -recognize that the force of attraction among oppositely charged ions is three-dimensional and results in the formation of a three-dimensional lattice
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Quarts, salt, sugar… Similarities and differences result from ways their atoms or ions are joined.
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Compound Review Made of two elements Chemical properties very different than original ingredients. https://www.youtube.com/watch?v=oZdQJi-UwYs https://www.youtube.com/watch?v=oZdQJi-UwYs
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Chemical bonds distinguish compounds from mixtures Compound v. mixture? Chemical bond: the attractive force that holds atoms or ions together. Blue and Yellow paint= What if you add more of one color? Hydrogen gas and oxygen gas= Bonds are broken and atom are rearranged. A compound always has the same chemical formula NaCl, H 2 0, C 6 H 12 O 6 Same elements in same proportions. This is true on Earth, outer space, or in your own body.
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Chemical structure shows the bonding within a compound. How things connect= chemical structure Chemical Structure: the arrangement of atoms in a substance. Compound=Rope Two terms to specify position of atoms Bond length: the average distance between nuclei of two bonded atoms Bond angle: the angle formed by two bonds of the same atom.
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Models of Compounds Ball and Stick (previous slide) Structural Formula Space Filling
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Compounds with network structures are strong solids. Quarts Compound… Every silicon atom is bonded to four oxygen atoms. Hard and inflexible. Takes a lot of energy to break making melting point and boiling point very high.
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Some compounds are made of networks of bonded ions. Sodium Chloride, salt (ionic compound) Tightly packed positive sodium ion and negative charged chloride ions. Formed by a transfer of electrons. Cations and Anions Typically form between metal and nonmetal.
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Some compounds are made of molecules Sugar (molecular compound) Made of molecules of carbon, hydrogen, and oxygen atoms joined by bonds. Two or more nonmetals share valence electrons to get a full outer shell. Bonds are not as strong resulting in lower melting points.
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Testing the attraction Bonds Solids=strongest Liquid=middle Gas=weakest Quick lab: What melts more easily, sugar or salt.
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Hydrogen Bonds One water molecule is attracted to a hydrogen atom of a neighboring water molecule. Dotted lines indicate intermolecular attractions… hydrogen bonding.
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