Chemistry Bonding Notes and Lewis Dot Structures

CChemistry Exam 2 Study Guide (10/07/12) I. stinging a. noggin Bonding i. Electrons are transferred ii. Ions are held together by electrostatic consequence b. Covalent Bonding iii. Electrons are nearlyhow shared out iv. Electrons are attracted to nuclei (shared) II. electr igativity c. The ability of an atom in a molecule to attract shared electrons to itself d. Measured on Pauling Scale e. Most electro prohibit Fluorine. Then Oxygen. f. Depending on electronegativity of X and Y, there are 3 possibilities v. X and Y have identical electronegativities (Non Polar) vi.X and Y have dissimilar electronegativities (Polar)- Y is reasonably negative has greater control than slightly positive X vii. X and Y have very different electronegativities ( loft)- Y is negative has exuberant control g. Polar Covalent viii. Size depends on electronegative struggle ix. Arrow points to where electrons are dragged to x. Dipole Moment measured in Debyes (D) 1. Dipole Momenti = Q*r xi. Possesses so me dome character 2. The bigger the difference a. The more diametrical the link b. The bigger the dipole c. The more ionic in character III.Electron abidance for Ions h. Atom forms an ion with electron configuration of the c sufferst noble turgidity xii. full-strength for representative S and P block xiii. Atom will lose up to three or gain up to three electrons 3. For D-block elements d. outer(a) S electrons lost in the lead outer D electrons 4. For P-block elements e. Outer P lost before the outer S electrons, which are lost before outer D IV. Ionic Radii i. Size descriptions based on luff xiv. Positive ions are always smaller than the parent atom xv. prohibit ions are always larger than the parent atom j.Periodic trend xvi. Ionic radii increase within a column going from top to fag xvii. Ionic radii decrease within a row going from leftfield to right V. Isoelectronic Ions k. Have the same number of electrons l. Radius decreases as nuclear number increases VI. Compounds m. Ionic xviii. High Melting buck and stewing Point (brittle solids) xix. meltable in polar solvents like water xx. Insoluble in nonpolar solvents like Hexane xxi. Metal and Nonmetal xxii. Any compound that conducts galvanising current when melted n. Covalent xiii. Low Melting Point and Boiling Point (solid/liquid/gas) xxiv. Insoluble in polar solvents (exception Sugar ) xxv. Soluble in nonpolar solvents xxvi. Nonmetal and Nonmetal o. Crystals xxvii. All group 1 Alkali metals and Group 7 Halogens make crystals xxviii. Sublimation solid to a gas VII. Lattice Energy p. Measure of how strongly ions interact together (compares sizes of ions) xxix. heat content of formation of the ionic compound from gaseous ions and as such is perpetually exothermic xxx. he efficacy required to completely separate one mole of a solid ionic compound into gaseous ionic constituents q. Goes to closer energy (emits energy as heat)- always more negative number r. (+) = endothermic (absorbing energy) s. (-) = exothermic (releasing energy) t. Energy is released xxxi. =K(Q1Q2)/(r) xxxii. Large for small r (average distance between ions)- higher boiling point, more stable, difficult to separate, but still fragile xxxiii. Large Q- highly charged xxxiv. Lattice energy goes down in same group VIII.Bond nightclub u. Triple Bond (as bond energy increases, bond length decreases ) xxxv. Highest Bond Order xxxvi. Strongest xxxvii. Shortest v. doubly Bond w. Single Bond xxxviii. Weakest xxxix. Longest xl. Lowest Bond Order IX. Resonance x. More than one Lewis Dot Structure can be drawn for the same arrangement (skeleton) of atoms. Only the bonds differ y. True construction is a hybrid or blend of possible resonance structures z. non double or single bonds, but all bonds with order 1. 3333 . shamble of electrons . Formal Charge li. Look at one atom at a time (sum of Formal Charge must add up to over all charge of structure) xlii. ( of valance e- on free atom) ( of a lonely(prenominal) (predicate) pair e-) + ( of bonds) X. Octet Rule Violators . Always OBEY the octet endure B, C, O, N, and F. . 5 EXCEPTIONS we should know xliii. ________________________ . Radical- odd number of electrons . Biradical- EVEN number of electrons has cardinal UNPAIRED electrons (O2) . Groups 5-8 (3rd row and lower can have more than 8 valance) XI. VSEPR Theory . Valance Shell Electron Pair Repulsion Bonds and lone pairs repel (more lone pairs= squeezed) . Determines the likely shape of a molecule . Does not describe how the bonding occurs . Steps xliv. Draw Lewis Dot Structure xlv. determine RHED (Region of High Electron Density) xlvi. Predict electronic geometry (arrangement of RHED) xlvii. Determine molecular geometry xlviii. are bonds polar? xlix. Is the molecule polar? . If dipoles cancel out (the same), it is non polar . Doesnt matter about net dipole direction, it will be polar . Pairs of diploes not arranged to cancel (different sizes)