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Chemical Bonds Polyatomic Ions Chemical Equations Reactions

Chemical Bonds Polyatomic Ions Chemical Equations Reactions. Review: -Compounds: When elements UNITE creating a NEW SUBSTANCE with NEW PROPERTIES Ex: Table Salt (NaCl = SodiumChloride) Na (Sodium)= shiny, soft, silvery metal that reacts violently with water

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Chemical Bonds Polyatomic Ions Chemical Equations Reactions

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  1. Chemical Bonds Polyatomic Ions Chemical Equations Reactions

  2. Review: -Compounds: When elements UNITE creating a NEW SUBSTANCE with NEW PROPERTIES Ex: Table Salt (NaCl = SodiumChloride) Na (Sodium)= shiny, soft, silvery metal that reacts violently with water Cl (Chlorine)= poisonous, greenish-yellow gas

  3. CHEMICAL FORMULAS • Tells what elements a compound contains • Tells the exact NUMBER of the atoms of each element in the compound • Contain SYMBOLS of the elements • Symbols have SUBSCRIPTS (written below) = tell how many atoms of that element are in the compound • Ex:H2O 2 atoms of Hydrogen 1 atom of Oxygen

  4. PRACTICE Sand = Silicon dioxide = SiO2 Cane Sugar = Sucrose = C12H22O11 Vinegar = Acetic Acid = CH3COOH

  5. REVIEW: -An atom is stable when its OUTER ENERGY LEVEL IS FULL (8 electrons or 2 electrons for Hydrogen and Helium) Ex: Noble Gases -Group 1 = 1 valence electron -Group 2 = 2 valence electrons -Group 3 = 3 valence electrons -Group 4 = 4 valence electrons -Group 5 = 5 valence electrons -Group 6 = 6 valence electrons -Group 7 = 7 valence electrons -Transition = 1, 2, or 3 valence electrons

  6. Elements can become stable by 1. GAINING electrons 2. LOSING electrons 3. SHARING electrons RESULT: 1. Elements become STABLE 2. COMPOUNDS form -Chemical Bond = holds atoms together

  7. IONS Sports Drinks = electrolytes = ions • An atom that has LOST or GAINED electrons • Have a CHARGE (+ or -) • Atom LOSES electrons = POSITIVE CHARGE (has more protons than electrons) • Atom GAINS electrons = NEGATIVE CHARGE (has more electrons than protons)

  8. IONS -Superscripts = (written above) = indicates an ions charge Ex: Potassium (K) loses one electron to Iodine to become stable. It now has a positive charge = K+ Iodine now has a negative charge = I- Potassium and Iodine are now IONS and are CHEMICALLY COMBINED = Compound is NEUTRAL

  9. TYPES OF BONDS • IONIC BOND -Between IONS with OPPOSITE CHARGES -Between METALS and NONMETALS -One atom LOSES electrons while another atom(s) GAINS electrons Ex: MgCl2 Mg 2+ (lost 2 e), Cl 1- = two Cl atoms each gained 1 e RESULT = NEUTRAL COMPOUND

  10. TYPES OF BONDS 2. COVALENT BONDS -Between atoms that SHARE electrons -Atoms share electrons because they can’t lose or gain electrons -Compound = NEUTRAL = called a MOLECULE -Form between NONMETALLIC elements -SINGLE COVALENT BONDS = 2 shared electrons -MULTIPLE BONDS = More than 2 shared electrons

  11. PREDICTION What type of bond will form between the following: 1. Carbon and Oxygen 2. Sodium and Oxygen 3. Phosphorus and Oxygen 4. Magnesium and Oxygen 5. Aluminum and Oxygen 6. Chlorine and Oxygen 7. Sulfur and Oxygen COVALENT IONIC COVALENT IONIC IONIC COVALENT COVALENT

  12. TYPES OF BONDS 3. METALLIC BONDS **Neither Ionic nor Covalent** -Happens between atoms in a metal -Positive Metallic Ions are surrounded by a cloud of electrons. -Electrons move freely around the positive ions Ex: Silver (Ag) + + + +

  13. POLARITY Due to unequal sharing of electrons -One end of a compound is more positive and the other end is more negative -”Tug of War” for electrons -”Having Opposite Ends” Polar Molecule = Slightly positive and slightly negative ends but molecule is NEUTRAL -Water: H2O

  14. SPECIAL IONS (YOU MUST MEMORIZE) NAME Oxidation # Copper (I) 1+ Copper (II) 2+ Iron (II) 2+ Iron (III) 3+ Chromium (II) 2+ Chromium (III) 3+ Lead (II) 2+ Lean (IV) 4+

  15. POLYATOMIC IONS (On your formulas sheet) NH4 + Ammonium C2H302 - Acetate (CH3COO-) Acetate ClO3 - Chlorate MnO4- Permanganate NO3- Nitrate OH- Hydroxide CO32- Carbonate CrO42- Chromate SO42- Sulfate PO43- Phosphate

  16. WRITING FORMULAS Write symbol of POSITIVE element/polyatomic ion first Write symbol of NEGATIVE element/polyatomic ion next Drag and Drop charges to subscripts Reduce subscripts to smallest whole numbers

  17. WRITING NAMES Write POSITIVE ION name If the ion has more than one oxidation number, write it with roman numerals. Write root name of NEGATIVE ION. (root is 1st part of element’s name) Add ending “-ide” to root Oxygen = oxide Phosphorus = phosphide Nitrogen = nitride Sulfur = sulfide

  18. WRITING NAMES for COVALENT COMPOUNDS Number of atoms Prefix 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- Use PREFIXES plus rules we’ve learned -Prefixes indicate the number of atoms of each element in a covalently bonded compound Ex: Carbon dioxide CO2 Carbon monoxide CO

  19. PRACTICE PROBLEMS PG. 621 #1-3 PG. 626 #1-19

  20. CHEMICAL REACTIONS • Change where one or more substances are changed into new substances • Ex. Sodium + Chlorine = Salt

  21. Chemical Equations • How we describe what goes on in a chemical reaction • Use FORMULAS and SYMBOLS • -Ex: • Na + Cl NaCl

  22. REACTANTS -Substances that REACT during the reaction -On the LEFT side of the equation -Ex: Na + Cl NaCl REACTANTS

  23. PRODUCTS -New substances that are PRODUCED from the reaction -On the RIGHT side of the equation -Ex: Na + Cl NaCl Product

  24. ARROW IN EQUATION -Means “PRODUCES” or “YIELDS” -Above the arrow, you tell whether HEAT, LIGHT, or ELECTRICITY were added to the reaction -Ex: Na + Cl NaCl Light Heat Electricity

  25. COUNTING ATOMS • NaCl Na=______________ Cl=_______________ • Al2O3 Al=_______________ O=________________ • Ca(PO4)2 Ca=__________ P=____________ O=______________ • 2Mg(CO3)2 • Mg= ____________ • C=___________ • O= _____________

  26. Conservation of Mass -Total Product MASS = Total Reactant MASS -No mass is ever lost or gained, it is conserved! -Ex: Na + Cl NaCl 1 g + 1g 2 g

  27. COEFFICIENTS • Tells how much of each substance is in the reaction • Always in front of the symbols or formulas • Ex: 2 H2 + O2 2 H2O 2 Guards + 2 Forwards + 1 Center 1 Team

  28. Combustion Reaction Synthesis Reaction Decomposition Reaction Single-Replacement Reaction Double-Replacement Reaction Exothermic Reactions Endothermic Reactions Reactions

  29. COMBUSTION RXN • When a substance reacts with OXYGEN and produces ENERGY in the form of HEAT and LIGHT • Ex. Burning Something • Ex. C + O CO2

  30. SYNTHESIS RXN • When 2 or more substances COMBINE to form another substance (one substance) • Ex. A + B AB • Ex. + • Ex. 2 H2 + O2 2H2O

  31. Decomposition Rxn -1 Substance BREAKS DOWN into 2 (or more) substances -Usually need HEAT to make this happen -Ex. AB A + B -Ex. + -Ex. 2H2O 2H2 + O2

  32. SINGLE-REPLACEMENT RXN • 1 Element REPLACES another Element in a compound • Ex. A + BC AC + B • Ex. + + • Ex. Cu + 2AgNO3 CuNO3 + 2Ag

  33. Double-Replacement RXN • -2 elements SWITCH positions • -”SWINGERS” = SWAP PARTNERS • Form 2 NEW COMPOUNDS and usually a PRECIPIATATE (insoluable compound) • Ex. AB + DC AC + DB • Ex. + +

  34. Exothermic Rxn • Reaction where HEAT IS RELEASED • Temperature INCREASES • Exo = EXIT

  35. Endothermic RXN • Reaction where HEAT IS ABSORBED • Temperature DECREASES • Endo = ENTER

  36. Controlling RXNS CATALYSTS INHIBITORS -Speed up - Slow down -Time decreases -Time increases

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