Chapter 12 Chemical Bonding

EXIT 2 Figure 12.4: The three possible types of bonds.

EXIT 3 Electronegativity – the ability of an atom to pull shared electrons toward itself in a bond Trend for electronegativity: it gets larger up and to the right (like ionization energy) trend does not apply to noble gases; F is the most electronegative element Polar – has a positive side and a negative side

EXIT 4 Figure 12.3: Electronegativity values for selected elements.

EXIT 5 Table >∆E>0 ∆E>2

EXIT 6 Ionic:metal and nonmetal Polar Covalent: two nonmetals Nonpolar Covalent: two identical nonmetals

EXIT 7 Bond polarity increases as difference in electronegativity increases (further apart on periodic table means more polar bond) Ionic character is the same thing only between metal and nonmetal.

EXIT 8 Classify the bond type: a) AsF 5 b) NaCl c) CO d) Cl 2 Put in order of increasing bond polarity: C-O, O-P, N-O, O-O, B-O Which is the positive side and which is the negative side of each bond?

EXIT 9 Classify the bond type: a) HCl b) Kr c) MgO d) Fe(NO 3 ) 3 Put in order of increasing ionic character: FeO, ZnCl 2, CaF 2, MgF 2, CuCl 2

EXIT 10 Figure 12.5: Charge distribution in the water molecule.

EXIT 11 Figure 12.5: Water molecule behaves as if it had a positive and negative end.

EXIT 12 Figure 12.6: Polar water molecules are strongly attracted to positive ions by their negative ends.

EXIT 13 Figure 12.6: Polar water molecules are strongly attracted to negative ions by their positive ends.

EXIT 14 Table 12.2

EXIT Forming Ions 15 Postive ions: Na Mg Negative ions: F N

EXIT 16 Table 12.3

EXIT Size of ions 17 Positive ions are smaller than neutral Negative ions are larger than neutral

EXIT 18 Figure 12.9: Relative sizes of some ions and their parent atoms.

EXIT Size of ions continued 19 Isoelectronic – having the exact same electron configuration When comparing sizes of ions that are isoelectronic, the one with the most protons is the smallest Put in order of increasing size: Ca 2+, P 3-, Cl -, K +, S 2-

EXIT 20 Which is larger and why? P 3- or Cl - Se 2- or K + O 2- or Na + Br - or Br

EXIT 21 Ionic = Lattice

EXIT 22 Lattice Energy Lattice energy is bond energy for an ionic bond Lattice energy = So lattice energy is: more for larger charges more for smaller ions The effect of charges is greater than the effect of size. __________ k(Q1Q2) r

EXIT 23 Which has the greater lattice energy? 1. NaCl or KCl 2. LiF or LiCl 3. Mg(OH) 2 or MgO 4. Fe(OH) 2 or Fe(OH) 3 5. NaCl or Na 2 O 6. MgO or BaS

EXIT 24 Bond Energy Always refers to covalent bonds Is stronger for triple bonds and weaker for single bonds You can use bond energies to calculate △H for a reaction