Chemical Bonds The Formation of Ions Atoms tend to lose or gain electrons that results in the...
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Transcript of Chemical Bonds The Formation of Ions Atoms tend to lose or gain electrons that results in the...
Chemical BondsChemical Bonds The Formation of Ions
Atoms tend to lose or gain electrons that results in the outermost shell being filled to capacity
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Chemical BondsChemical Bonds The Formation of Ions
Why does Cl attract another electron if its neutral?
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Position Probabili
ty
Chemical BondsChemical Bonds Covalent Bonds
Atoms held together by their mutual attraction for shared electrons
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Non-polar molecule Polar molecule
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+
Chemical BondsChemical Bonds Metallic Bonds
The positive metal ions are held together by a “fluid” of free electrons removed from the outer shells of the metal atoms
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Chemical BondsChemical Bonds
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Chemical BondsChemical Bonds Bonds between molecules, not within molecules
• Usually involves dipoles with PE ~ 1/rUsually involves dipoles with PE ~ 1/r66
• Important in liquids and solidsImportant in liquids and solids
DNA has weak H bonds between each strand of the molecule
• Broken by molecular collisionBroken by molecular collision• Important in protein synthesisImportant in protein synthesis
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Chemical BondsChemical Bonds
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Chemical BondsChemical Bonds Natural Sources to Pure Metals
Ores – materials containing high percentage of a mineral that make extraction feasible.
• Concentrated by floatation after grinding into a powder.
Refining removes the impurities by heating (slag formation) or chemical reactions (electrolysis)
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Chemical BondsChemical Bonds Natural Sources to Pure Metals
Alloys – mixtures of metals or with a nonmetal that have properties more desirable than the pure metal.
Cu + Au → increased hardness of gold
Ni + Cr + Fe → iron is less likely to rust
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Chemical BondsChemical Bonds Natural Sources to Pure Metals
Cast iron – brittle when cold• Engines, boilers, stoves, cookware, pipes
Wrought iron – hardened iron by hammering out remaining impurities.
• Fences, gates, grills
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Chemical BondsChemical Bonds Natural Sources to Pure Metals
Carbon steel: < 1.5% C + Fe• Beams, girders, rebar, cutting tools, railroad
rails
Stainless steel: Ni + Cr + Fe• Cutlery, chemical plants, ornaments for
buildings
Silicon steel: Si + Fe• Transformers, motors, generators
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Chemical BondsChemical Bonds Polymers
Large molecules made of carbon chains
Synthetics – rayon, cellophane, plastics, rubber, polyester, Velcro, medical (hip, skin, artery)
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Chemical BondsChemical Bonds Composites
Heterogeneous mixture that exploits the desired structural and mechanical properties of each material
• Fiber-reinforced polymers: fiberglass with resin
• Light weight and strong – automobile bodies, fishing rods, bicycle frames, bathtubs
• Kevlar
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