REVIEW CLASS FOR NOVEMBER 7, 2007

1. REVIEW CLASS FOR NOVEMBER 7, 2007 #1) DURING BONDING POTENTIAL ENERGY DECREASES IN ALL BONDING, BOND FORMATION IS EXOTHERMIC ALWAYS ---(1) #2) N + N  N2 THE TWO N ATOMS COMBINE(BOND) TO FORM N2 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), MgCl2 IS IONIC. Also Mg is a metal from the left and S is a nonmetal. – (1)

2. #8) GROUP ONE METALS CAN ONLY BOND IN IONIC BONDING. Na IN Na2O IS IN GROUP ONE. ALSO THE IONIC CHARACTER BETWEEN Na AND O IS 2.6, WHICH IS IONIC. --- (2) #9) THE GREATEST IONIC CHARACTER (1.9) IS IN HF ..(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) #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)

3. #15) THE LEAST IONIC CHARACTER IS CO2, -- (1) Cl H Cl H #16) THE TRANSFER OF ELECTRONS OCCURS ONLY IN AN IONIC BOND. Na2O 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) F2 IS IN H2, O2, N2, Cl2, Br2, I2, F2 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)

4. #21) THE IONIC CHARACTER BETWEEN H AND Br IS 0.90, WHICH IS POLAR COVALENT ( FROM ABOUT .4 UP TO 1.7)—(2) N #22 THE IONIC CHARACTER BETWEEN O AND H IS 1.4, WHICH IS VERY POLAR AND COVALEN -- (4)) BOTH OF THESE ELECTRONS ARE FROM THE NITROGEN; WHEN ONE ATOM CONTRIBUTES BOTH ELECTRONS IT IS CALLED COORDINATE COVALENT BONDING H #23)--(4) #24)--(4) + H H BOTH N AND H CONTRIBUTE ONE ELECTRON, THIS IS A COVALENT BOND, POLAR DUE TO A N TO H IONIC CHARACTER OF 0.9. H

5. #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. C6H12O6 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)

6. REVIEW CLASS PAGE 4:27 HIGH IONIC CHARACTER MORE UNEQUAL SHARING OF ELECTRONS GREATER POLARITY STRONGER ATTRACTIONS #1) CH4 IS TETRAHEDRAL (RECOGNISE CENTRAL CARBON WITH 4 SINGLE BONDS, NO ELECTRON PAIRS). THIS IS SUMMETRICAL –(2) #2) H2O 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) H2O HAS THE GREATEST IONIC CHARACTER, SEE BELOW.—(2) #5) HYDROGEN BONDING ATTRACTIONS OCCUR IN COVALENT MOLECULES WHERE HYDROGEN IS BONDED TO F,O,N IN ASYMETRICAL MOLECULES.

7. #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 131.1 g/mol)—(4) #7) H2 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)

8. #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)

9. #17) CHEMICAL FORMULAS REPRESENT BOTH ATOMS AND COMPOUNDS. #18) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, K2O IS IN MOST REDUCED FORM –(1) #19) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, CH4 IS IN MOST REDUCED FORM –(1) #20) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, CH2O IS IN MOST REDUCED FORM –(4) #21) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, H2O IS IN MOST REDUCED FORM –(2) #22) THE MOST REDUCED SUBSCRIPTS REPRESENT AN EMPIRICAL(SIMPLE) FORMULA, P2O5 IS IN MOST REDUCED FORM OF P4O10 --(3)

10. #23) LEAD (11) = Pb+2 Pb+2 (PO4)-3 Pb3 (PO4)2 --(3) CRISS-CROSS #24) Ca+2 CAUSE IT IS IN GROUP 2 Ca+2 (PO4)-3 Ca3 (PO4)2 --(4) CRISS-CROSS #25) FROM TABLE E, NO3- NITRATE AND ClO3- CHLORATE BOTH HAVE OXYGEN. #26) N+1 O-2 N2O--(2) CRISS-CROSS,REMENBER O-2 IS OXIDE