Lewis Dot only shows the number of valence electrons doesn t indicate structure Electronegativity ability of an atom to attract an electron in a chemical environment Increases from L R decreases from top bottom Electronegativity difference tells how 2 elements will interact If 2 elements are the same they have NO E N difference E N difference 0 0 0 4 Non Polar E N difference 0 4 2 0 Polar E N difference 2 0 Ionic Bond Ionic Bond transfer of electrons metals bond with non metals o E N difference of 2 0 Polar Covalent Bond electrons shared UNEQUALLY o E N difference 0 4 to 2 0 o HAS MOLECULAR DIAPOLE molecule is distorted Non Polar Covalent Bond electrons shared EQUALLY o E N difference of 0 0 to 0 4 o NO MOLECULAR DIAPOLES Oxidation state IONIC LIMIT partition electrons in bonds to the most E N elements o Give both electrons in a bond to the most E N element For simple monatomic ion the O S charge on ion o o Charge of ions due to complete transfer Formal charge COVALENT LIMIT partition electrons in bonds equally between atoms o o For a shared pair of electrons between atoms give 1 electron to each atom Formal charges go to the MOST E N ELEMENT Octet Rule cannot have more than 8 valence electrons only C N O F follows this Hybrid orbitals used to form Sigma Bonds and hold lone pair Unhybridized p orbitals required for Pi Bonds Empirical Formula ratio of atoms in compound LOWEST WHOLE NUMBER RATIO Combustion any reaction with Oxygen gas Lattice Energy The higher the charge state the stronger the lattice energy Increase in size increase in distance so lattice energy decreases as atoms get larger Decreases top bottom increases from left right Sigma Bond No nodes between atoms Strongest type of bond Always form sigma bonds first Only ONE sigma bond between ANY 2 ATOMS Pi Bond Have a node along internuclear axis Only forms with double or triple bonds double bond has 1 Pi Bond triple has 2 Unhybridized orbitals pure p orbitals Lewis Dot Structure 1 Add up the number of valence electrons be careful of charge 2 Draw the skeletal structure i Hydrogen most E N on the OUTSIDE 3 Distribute remaining electrons as Lone Pairs i Most E N gets electrons first fill central octet last ii Hydrogen is a duet 4 Move lone pairs to bond pairs to satisfy central atom octet if necessary i Best Lewis Dot has LOWEST FORMAL CHARGE ii Formal charges go on the most E N elements iii The sum of formal charges should equal the charge of the compound 5 Draw Resonance structures VESPR structure 1 Write the best Lewis Dot structure minimize formal charge 2 Assign Electron Group number 3 Determine electron group geometry and molecular geometry shape 4 Draw evaluate distortions from lone pairs and double bonds LP LP LP BP BP BP minimize at 90 degrees ignore 90 degrees Calculate Mass Composition 1 Take 1 000 moles of the compound 2 Calculate molar mass total weight 3 Calculate grams of each element 4 Divide the weight of each element by the molecular mass Calculate Empirical Formula 1 Take 100 0g of the compound 2 Calculate mass and moles of each element 3 Write PSEUDOFORMULA of compound 4 Divide all subscripts by smallest number 5 If subscripts aren t whole numbers MULTIPLY by small numbers until all are WHOLE NUMBERS
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