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Unit 11 Chapter 12. Chemical Bonding. Sunprint Poper Photography Designed by John Herschel In the 1840’s. Blue color is caused by an insoluble compound called Prussian blue Fe 4 [Fe(CN) 6 ] 3. High. Energy - Low.
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Unit 11 Chapter 12 Chemical Bonding
Sunprint Poper Photography Designed by John Herschel In the 1840’s Blue color is caused by an insoluble compound called Prussian blue Fe4[Fe(CN)6]3
High Energy - Low Above is the full electromagnetic spectrum. Humans see only a small portion of it, just the visible region.
The e- in the outer energy level are called valence e-. These e- are involved in bonding one atom to another atom. If the atom is Al, there are 13 p+, 14 n, and 13 e -. 2 e- in the 1st energy level, 8 e- in the 2nd energy level, and 3 e- in the 3rd energy level. The 3 e- in the outer energy level are involved with bonding.
General Rule: All of the elements want to have the same number of electrons as their nearest noble gas neighbor. H He Li Be B ____ ____ ____ ____ ____ O F Ne Na Mg Al ____ ____ ____ ____ ____ ____ S Cl Ar K Ca ____ ____ ____ ____ ____ * * *
Lewis symbols: The symbols represent the nucleus and all inner energy level e-. Dots represent valence e- (the outer energy level e-).
Types of Bonding: • Ionic Bonding – between a metal & non-metal Transfer of e- resulting in a positive ion and a negative ion that are attracted to each other. Metal – valence orbitals are emptied Non – metal – valence orbitals fill to have the configuration of the next Noble gas. The metal (cation) is attracted to the nonmetal (anion) because of opposite charges. [ ]
Bond the following Ionically:Sodium & chlorineMagnesium & chlorineBarium & oxygenAluminum & oxygen
Covalent Bonding: between Non-metals, It is a sharing of e- in such a way as to complete the valence orbitals of both (all) atoms. All atoms end up with the e- configuration of Noble gases. Steps for determining covalent bonding: • Determine the total number of valence e- • Write the skeleton structure and join the atoms in this structure by a single covalent bond. • For each single bond, subtract 2 from the total number of valence e- • With the remaining valence e-, first complete the octets of the terminal atoms, then the central atoms. • If a central atom lacks an octet, form multiple covalent bonds by converting lone – pair e- from terminal atoms into bonding pairs.
Steps for determining covalent bonding:1. Determine the total number of valence e-2. Write the skeleton structure and join the atoms in this structure by a single covalent bond.3. For each single bond, subtract 2 from the total valence e-4. With the remaining valence e-, first complete the octets of the terminal atoms, then the central atoms.5. If a central atom lacks an octet, form multiple covalent bonds by converting lone – pair e- from terminal atoms into bonding pairs. Bond the following: F2 PI3 NH3 O2
Bond the following covalently: H2O N2 CH3CHO
Sometimes the e- are not distributed evenly throughout the molecule. • :O – H • H Molecules that have this appear to have a positive charge on one side, and a negative charge on the other side. d - . . d +
Polar Covalent Bonding: an uneven sharing of e- in a covalent bond. The e- tend to be concentrated around one atom more than the other atom. Which of the above are polar?
Bond Angles : Molecules will bond with specific angles between the bonds. • Determine the covalent bonding on paper • Build the molecule using the molecule kits • Measure the angle of the bonds marked Using the Molecule Model Kits Atoms : Colors Hydrogen : yellow Oxygen : red Carbon : black Nitrogen : blue Chlorine : green Bonds Single -one pair of e-, Use 1 wooden peg Double = two pair of e-, Use 2 springs Triple three pair of e-,Use 3 springs
Fabric Dyeing All groups will complete Part 1 – Direct dyeing : Choose your color Methyl orange, Malachite green, Rainbow mystery either Part 2 -Substantive dyeing or Part 3 -Vat Dyeing Part 4- Mordanted Cloth dyeing : Choose Fe+2 or Cu+2 Use the same color as in part 1 Put the fabric in the beakers to begin, then mix up laundry soap and bleach or acid rinse (check your labs).
Test Fabric Strip • Filament acetate (black line) • SEF (Modacrylic) • Filament Triacetate • Bleached Cotton • Creslan 61 (Acrylic) • Dacron 54 (Polyester) • Dacron 64 (Polyester) • Nylon 66 (Polyamide) • Orlan 75 (Acrylic) • Spun Silk • Polypropylene (Polyolefin) • Vicose (Rayon) • Wool (Worsted)
Dyes & Dyeing Lab How do dyes bond to the fabrics? Silk & Wool – proteins : polar or ionic site Dacron & Orlon : few polar sites Nylon : very few polar sites Easy to dye Hard to dye
The fabric will dye using different types of bonding: Covalent bonding