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Periods Families(Groups) -- same # valence electrons. Non-Metals. Metals. Metalloids. As a general rule, metals don’t like to form bonds(compounds) with other metals(They will with themselves). Metals(+ ions) would rather form bonds with nonmetals(- ions)!!. Covalent Bonding.
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Periods Families(Groups) --same # valence electrons Non-Metals Metals Metalloids As a general rule, metals don’t like to form bonds(compounds) with other metals(They will with themselves). Metals(+ ions) would rather form bonds with nonmetals(- ions)!!
Covalent Bonding • Involves the sharing of electrons. • Covalent bonds form between nonmetals and nonmetals.
Lewis Dot Structures(aka Electron Dot Diagrams) • Lewis dot structures are a shorthand to represent the valence electrons of an atom. • The structures are written as the element symbol surrounded by dots that represent the valence electrons.
Lewis Dot Structures(cont.) • Lewis structures can also be used to show covalent bonding between atoms. • The bonding electrons are placed between the atoms and can be represented by a pair of dots or a dash (each dash represents one pair of electrons, or one bond).
Show the Lewis Dot Structures for the following compounds: O2 F2 H2O
Covalent Bonds(cont.) • Sometimes electrons are shared equally among nonmetals in a covalent bond. Sometimes they are not. • It’s as if one element is pulling on the electrons just a little bit harder than the other.
Covalent Bonds(cont.) Polar Covalent Bonds Non-Polar Covalent Bonds Both elements are pulling just as hard on the electrons. Equal sharing of electrons. • One element is pulling harder on the electrons than the other(s). • Unequal sharing of electrons. • This cause them to set up “poles”. • One element will become slightly positive and the other slightly negative.
Solutions with Polar and Non-Polar Compounds: • As a general rule, “Likes dissolve Likes” • Polar substances dissolve polar substances! • Ex. H2O dissolves NaCl(all ionic compounds are polar) • Non-Polar substances dissolve Non-polar substances. • CO2 will dissolve in ethanol(CH3CH2OH) because both are non-polar. • Polar substances will not dissolve in Non-Polar substances!!! • Water and Oil do not mix!!!
Which compound is least affected by temperature? Which compound’s solubility decreases as temperature increases?
How many grams of KNO3 will dissolve in 100 g of water at 60o C? 110 g
At what temperature will approximately 95 g of NaNO3 dissolve in 100 g of water? 30 oC
At what temperature will the same amount of KNO3 and NaNO3 dissolve in 100 g of water? ~ 68 oC
Name the following compounds: Sodium Chloride • NaCl • CaO • KF • Na2CrO4 • Ca(ClO3)2 • Al2(CO3)3 Calcium Oxide Potassium Fluoride Sodium Chromate Calcium Chlorate Aluminum Carbonate
Writing Chemical Formulas: Lithium and Selenium Li+1Se-2 Li2Se Calcium and Chlorate Ca+2ClO3-1 Ca(ClO3)2 Beryllium and Phosphorus Be+2P-3 Be3P2 Gallium and Carbonate Ga+3CO3-2 Ga2(CO3)3
Write the formulas for the following compounds: • Calcium Phosphate Ca+2PO4-3 Ca3(PO4)2 • Aluminum Acetate Al+3C2H3O2-1 Al(C2H3O2)3 • Francium Phosphide Fr+1P-3 Fr3P
Determine the oxidation state of both elements in the following examples: • CuF2 Cu+2F-1 • Co2S3 Co+3S-2 • Fe2O3 Fe+3O-2
Chemical Equations: • Reactants “yield” Products • Reactants Products • Must know the 4 types of chemical reactions: • Decomposition AB A + B • Synthesis A + B AB • Single Replacement AB + C AC + B • Double Replacement AB + CD AD + CB