Cell Chemistry (I) Inorganic Compounds Chemical Bonds Solutions and pH.
Chemistry Unit 3 Chemical Bonds
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Transcript of Chemistry Unit 3 Chemical Bonds
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Chemistry Unit 3Chemical Bonds
Valence ElectronsDot Diagrams
Oxidation numbersTypes of Bonds
PolyatomicsTransition elements
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Valence ElectronsThe number of electrons in the outer energy level involved in bonding.Equal to the ‘group number’ (except 3-12).Found in loop and cross diagrams.
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Dot DiagramsUsed to show the valence electrons with the symbol. .
H And N. .. ...
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WB Practice!AluminumBoron
SulfurCalcium
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Oxidation Numbers•The number of electrons that an element would like to gain or lose to complete its outer valence shell.•All atoms and compounds want to have a complete outer shell.•8 electrons (An Octet) completes any outer shell.•They come from the valance electrons.
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Oxidation NumbersFrom valence electrons:
Valence 1-3 want to lose.Valence 5-7 want to gain.Valence of 4 can go either way.
So… H, Li, and Na have oxidation numbers of 1+ because they would like to give one electron away to be ‘stable’.
While… F, Cl and Br has oxidation numbers of 1- because they would like to get one electron to be ‘stable’.
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Types of BondsIonic:
Where electrons are lost and gained between atoms.Mainly between metals and non-metals.Uses the Oxidation number
Covalent:Where electrons are shared between atoms.Between two non-metals.You must be given the number of each element used.
For BONDING:Elements to RIGHT of the stair step are NON-metalElements to the LEFT of the stair step are METAL
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Examples of Ionic Compounds
Sodium and Chlorine: (Na 1+ and Cl 1-) is NaCl
Potassium and Bromine: (K 1+ and Br 1-) is KBr
Magnesium and Oxygen: (Mg 2+ and O 2-)
is MgOCalcium and Sulfur: (Ca 2+ and S 2-)
is CaS
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Ionic Bonds DemoHydrogen and Oxygen:
So it takes 2 Hydrogen to bond with one oxygen.
Calcium and Chlorine:
So it takes 2 Cl to bond with 1 Ca)
1+ 2-HO 2+
1-Ca Cl
2H2O
1CaCl2
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Ionic Bonds - NOTICEIn the final answer – if the subscripts would match, we leave them off.The positive oxidation always comes first.Pay very close attention to capital and lower case and the placement of the subscript.
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Ionic Bond Practice
Combine: Potassium and SulfurMagnesium and NitrogenCalcium and PhosphorousAluminum and Chlorine
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Examples of Covalent
1 Carbon and 1 Oxygen is CO
1 Carbon and 2 Oxygen is CO2
1 Phosphorous and 3 Chlorine is
PCl3
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Covalent Bond PracticeCombine:
1 Silicon and 4 Fluorine2 Nitrogen and 3 Sulfur1 Hydrogen and 1 Bromine2 Bromine
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PolyatomicsCovalent compounds that are “pre-formed” with unique names and charges (oxidations).They can and will ionically bond with other compounds and elements.
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Poly Oxidation 1- (FS)Name
AcetateBicarbonateChlorateHydroxideNitrateNitriteCyanide
FormulaC2H3O2
HCO3
ClO3
OHNO3
NO2
CN
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Poly OXIDATION 2- (FS)Name
CarbonateChromatePeroxideSulfateSulfiteSilicate
FormulaCO3
CrO4
O2
SO4
SO3
SiO3
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Poly – Other Oxidations (FS)Oxidation -
Name3- Phosphate1+ Ammonium1+ Ammonia1+ Hydronium0 Methane
FormulaPO4
NH4
NH3
H3OCH4
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Polyatomic Ionic ExamplesCombine:
Aluminum (Al 3+) and Sulfate (SO4 2-)Al2(SO4)3
Potassium (K 1+) and Nitrate (NO3 1-) KNO3
Ammonium (NH4 1+) and Chlorine (Cl 1-)NH4Cl
Ammonium (NH4 1+) and Nitrate (NO3 1-)NH4NO3
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Polyatomic PracticeCombine:
Barium and HydroxideCalcium and SulfateAmmonium and HydroxideLithium and Nitrate
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Transition Elements
The transition elements get their name because they have variable oxidation numbers.Their oxidation numbers are always positive.You are told or given a transition elements oxidation number with a roman numeral.They will bond Ionically with other elements and compounds.
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Transition Ionic Examples
Combine:Copper (I) and Oxygen (Cu2O) since Cu 1+ and O 2-
Iron (III) and Chlorine (FeCl3) since Fe 3+ and Cl 1-
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Transition Ionic PracticeCombine:
Lead (II) and CarbonateGold (III) and SulfurNickel (II) and NitrateTin (II) and Fluorine