1. Chemical Bonding Why? To achieve stability (happiness)  Lower energy level  8 electrons –react so as to achieve the valence level configuration of NEAREST inert gas How? 1. Ionic Bond: ◦Transfer of electrons from Metal (low IE/EN) to non-metal (High IE/EN) ◦Larger difference in IE/EN 2. Covalent Bond:  between NON-metals  b/w items with similar IE/EN (small difference)  Due to SHARING of electrons 

2. 2. Covalent Bond:  between NON-metals  b/w items with similar IE/EN (small difference)  Due to SHARING of electrons * In a given covalent bond each element contributes 1 electron to the pair shared* *BOND FORMATION: due to an overlap of atomic orbitals on the valence level * Identical Bonds: identical in every way, strength, length etc

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4. Bonding cont’d Sigma Bonds: the first bond formed between two atoms - it will use hybrid orbitals Pi Bond ( π bond): the second/third bond formed between two atoms PURE ‘P’ for PI bonds

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6. So..... Why do we care??? Knowing # of bonds and # of lone pairs allows us to determine shape of a molecule and then in term helps to determine polarity!! Woot woot

7. Remember hyperlink on title VSEPR Theory Valence Shell Electron Pair Repulsion Theory  Electron pairs around the atom place themselves AS FAR APART as possible (Bonding or nonbonding lone pairs)  Determines geometry of a molecule based on Lewis structures  Lone pairs on the central atom have basically the same affect as a bonded pair of e -

8. Electron Pair Geometry 3 e - pairs4 e - pairs 5 e - pairs 6 e - pairs

9. Variations on Trigonal Planar

11. seesaw

14. Polarity – Bonds and Molecules Bond Types: 1. Ionic: transfer of electrons 2. Covalent: equal sharing of e - pair 3. Polar Covalent: unequal sharing of e - pair, creates dipoles (slight charges), determined by Δ EN of the elements

15. Determining Polarity smartboard

16. Classify the following as polar or nonpolar A) BeI 2 b) CF 4 c) CH 2 O d) CO 2 e) BF 2 Cl f) CH 3 Cl g) SF 6 h) SCl 2

17. Intermolecular Forces Two types of forces 1. Intramolecular: within a molecule (ionic/covalent bonds) 2. Intermolecular: between molecules

18. Wrap up Video Intermolecular Forces

19. Work: pg. 260 ◦#1)a,b,f 2) a,d 3) b,c 4. a) b) 5) think about it Pg. 264 #9) a,d 11 Pg. 266 #5, 7 – great test questions