REVIEW CLASS FOR NOVEMBER 7, 2007 #1) DURING BONDING POTENTIAL ENERGY DECREASES IN ALL BONDING, BOND FORMATION IS EXOTHERMIC ALWAYS ---(1) #2) N + N  N 2 THE TWO N ATOMS COMBINE(BOND) TO FORM N 2 THEREFORE A BOND IS FORMED AND ENERGY IS RELEASED (EXOTHERMIC) --(4) #3) ACCORDING TO TABLE “S”, Na has the smallest value for electronegativity. Also group one metals are low in electronegativity. –(1) #4) ACCORDING TO TABLE “S” SULFER (S) HAS THE HIGHEST ELECTRONEGATIVITY ---(3) #5) OXYGEN IS THE MOST ELECTRONEGATIVE AND WOULD EXERT THE GREATEST ATTRACTION FOR THE ELECTRONS. – (2) #7) BASED ON IONIC CHARACTER (1.9), MgCl 2 IS IONIC. Also Mg is a metal from the left and S is a nonmetal. – (1)

#8) GROUP ONE METALS CAN ONLY BOND IN IONIC BONDING. Na IN Na 2 O IS IN GROUP ONE. ALSO THE IONIC CHARACTER BETWEEN Na AND O IS 2.6, WHICH IS IONIC. --- (2) #10) NaF, NOTICE ALL AR BONDED TO F, THERFORE THE LEAST ELECTRONEGATE METAL WILL HAVE THE GREATEST IONIC CHARACTER. #11) HI HAS THE LEAST IONIC CHARACTER BASE ON TABLE “S” ELECTRONEGATIVITIES – (4) #9) THE GREATEST IONIC CHARACTER (1.9) IS IN HF..(2) #12) Sr IS A GROUP TWO METAL, METALS LOSE ELECTRONS WHICH MEANS THE ION IS POSITIVE AND HAS FEWER ELECTRONS THAN THE ATOM, THE ATOM HAS A GREATER NUMBER OF ELECTRONS –(1) #13) CHRYSTALLINE AND CONDUCTIVE IN THE THE MELTED STATE ARE IONIC CHARACTERISTICS –(1) #14) IONIC LIQUIDS ARE CONDUCTORS, NaCl (aq) IS SUCH A SUBSTANCE (BASED ON IONIC CHARACTER IT IS IONIC). ALSO ALL GROUP ONE METAL SALTS (Na IN THIS SALT) ARE SOLLUBLE AND CONDUCTIVE. –(2)

#15) THE LEAST IONIC CHARACTER IS CO 2, -- (1) #16) THE TRANSFER OF ELECTRONS OCCURS ONLY IN AN IONIC BOND. Na 2 O IS THE ONLY IONIC SUBSTANCE (IONIC CHARACTER IS 2.6, AND Na IS IN GROUP ONE WHICH INDICATES AN IONIC COMPOUND)—(4) #17) NON POLAR COVALENT BONDS ARE EQUALLY SHARED ELECTRONS BY DEFINITION. –(3) #18) F 2 IS IN H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2 WHICH ARE ALL NONPOLAR (BONDED TO ONE OF ITS OWN ELEMENT TYPE, IONIC CHARACTER =0 FOR THE BOND)---(2) #19) IONIC CHARACTERS BELOW 1.7 ARE COVALENT, WHERE ELECTRONS ARE SHARED ---(3) #20) Cl H H

#21) THE IONIC CHARACTER BETWEEN H AND Br IS 0.90, WHICH IS POLAR COVALENT ( FROM ABOUT.4 UP TO 1.7)—(2) #22 THE IONIC CHARACTER BETWEEN O AND H IS 1.4, WHICH IS VERY POLAR AND COVALEN -- (4)) #23)--(4) #24)--(4) N H H H H BOTH OF THESE ELECTRONS ARE FROM THE NITROGEN; WHEN ONE ATOM CONTRIBUTES BOTH ELECTRONS IT IS CALLED COORDINATE COVALENT BONDING BOTH N AND H CONTRIBUTE ONE ELECTRON, THIS IS A COVALENT BOND, POLAR DUE TO A N TO H IONIC CHARACTER OF

#25)CARBON DIOXIDE HAS AN IONIC CHARACTER OF 0.9, WHICH IS COVALENT AND ALL COVALENT BONDS FORM MOLECULES (MOLLECULAR).—(1) #26) NaCl IS IONIC (Na is in group 1), Cu(s) is metallic, KF is ionic. C 6 H 12 O 6 all bonds are covalent. C-O is 0.9, H to O is 1.4, and H to C is 0.5: all covalent!—(2) #27) COVALENLY BONDED COMPOUNDS ARE NEVER CONDUCTIVE, SOFT AND MOLECULAR – (1) #28) By definition it is covalent network solid, --(1) #29) THE ONLY SOLID CONDUCTORS ARE METALS (SEA OF ELECTRONS) –(1) #30) THE ONLY SOLID CONDUCTORS ARE METALS (SEA OF ELECTRONS)AND CALCIUM IS THE ONLY METAL HERE! –(3)

REVIEW CLASS PAGE 4:27 #1) CH 4 IS TETRAHEDRAL (RECOGNISE CENTRAL CARBON WITH 4 SINGLE BONDS, NO ELECTRON PAIRS). THIS IS SUMMETRICAL –(2) #2) H 2 O IS POLAR DUE TO THE CENTRAL OXYGEN HAVING 2 BONDS AND TWO ELECTRON PAIRS – BENT GEOMETRY WHICH IS ASYMETRICAL. – (3) #3) THE SMALL AND ELECTRONEGATIVE CENTRAL ATOM IS ABLE TO GRAB A LARGE SHARE OF THE ELECTRONS IN THE BOND – (3) #4) H 2 O HAS THE GREATEST IONIC CHARACTER, SEE BELOW.—(2) HIGH IONIC CHARACTER MORE UNEQUAL SHARING OF ELECTRONS GREATER POLARITY STRONGER ATTRACTIONS #5) HYDROGEN BONDING ATTRACTIONS OCCUR IN COVALENT MOLECULES WHERE HYDROGEN IS BONDED TO F,O,N IN ASYMETRICAL MOLECULES.

#6) DISPERSION FORCES (Van der Waals) are strongest in particles with the largest molar mass.Theyare weakest in particles with the smallest molar mass. He (4.0 g/mol) is the lightest of these and has the weakest dispersion forces. Xe would have the strongest, molar mass g/mol)—(4) #7) H 2 is nonpolar, and had dispersion forces as do all non-polar substances. (4) #8) DISPERSION FORCES WEAKEN AS PARTICLES BECOME LIGHTER. IN TERMS OF MOLAR MASS Xe>Kr>Ar>Ne, THIS DECREASE IS ALSO THE ORDER OF STRENGHT OF DISPERSION FORCES, WHICH DECLINE –(4) #9) DISSOLVING IS THE ATTRACTION OF A METAL ION TO WATER MOLECULES –(2) #10) Ca IS A METAL FROM GROUP 2, IT IS AS AN ION Ca +2, WHICH ATTRACTS TO THE NEGATIVE POLE OF WATER WHICH IS OXYGEN—(1) #11) KCl IS IONIC, DISSOLVES BY MAKING MOLECULE TO ION ATTRACTIONS – (3)

#12) MOLECULE TO ION –DISSOLVING. #13)(1) #14) MOLECULE-ION ATTRACTIONS (DISSOLVING) ARE FOUND IN AQUEOUS SOLUTIONS OF IONIC SUBSTANCES, IN THIS CASE KCl (AQ)- (4) #15)POSITIVE ION ATTRACTS TO NOGATIVE POLE, O.—(4) - +- #16) MOLECULE-ION ATTRACTIONS (DISSOLVING) ARE FOUND IN AQUEOUS SOLUTIONS OF IONIC SUBSTANCES, IN THIS CASE NaCl (AQ)-(1)

#17) CHEMICAL FORMULAS REPRESENT BOTH ATOMS AND COMPOUNDS. #18) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, K 2 O IS IN MOST REDUCED FORM –(1) #19) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, CH 4 IS IN MOST REDUCED FORM –(1) #20) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, CH 2 O IS IN MOST REDUCED FORM –(4) #21) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, H 2 O IS IN MOST REDUCED FORM –(2) #22) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, P 2 O 5 IS IN MOST REDUCED FORM OF P 4 O 10 --(3)

#23) LEAD (11) = Pb +2 Pb +2 (PO 4 ) -3 Pb 3 (PO 4 ) 2 --(3) CRISS-CROSS #25) FROM TABLE E, NO 3 - NITRATE AND ClO 3 - CHLORATE BOTH HAVE OXYGEN. #24) Ca +2 CAUSE IT IS IN GROUP 2 Ca +2 (PO 4 ) -3 Ca 3 (PO 4 ) 2 --(4) CRISS-CROSS #26) N +1 O -2 N 2 O --(2) CRISS-CROSS, REMENBER O -2 IS OXIDE