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Unformatted text preview: Chemical Bonding Ionic (electrostatics forces-Coulombs Law) Covalent (electron sharing) Practice problems Ch 4 3, 9, 11, 15, 19, 25, 29 Bonding Shades of Gray Complete Sharing Elements with identical EA HH ClCl Diamond Complete transfer Na + Cl- Alkali/Halogen Elements with very different EA Partial transfer Elements with similar EA AgCl SiO 2 CdS IONIC COVALENT Section 4.1 CHAPTER 4: The Ionic Bond Metals have low ionization energies (IE) they prefer to lose e s and become cations Non-metals have high electronegativities (EN) they prefer to gain e s and become anions When an electron is transferred from a metal to a non-metal, an ionic bond is formed. Section 4.1 2p 2s Cl 3s Na e lowers its energy 2p 2s Cl 3s Na + NaCl is an ionic compound. An ionic bond is formed between Na + and Cl . If E isnt big enough, the e s are shared and a covalent bond is formed (Chapter 5). Section 4.2 Ionic Radii: Cations get smaller! Z eff increases due to decreased shielding, remaining e s are held tighter Anions get larger! Z eff decreases due to increased shielding each e is held a little looser See Figures 4.1a and 4.1b Section 4.1 Anions: When a non-metal gains electrons, it becomes an anion Change its name by adding - ide to the end Ex. chlorine chloride oxygen oxide sulfur sulfide Non-metals will gain enough electrons to fill their outer shell Ex. ([Ne]3s 2 3p 5 ) Cl + e Cl [Ar] ([He]2s 2 2p 4 ) O + 2e O 2 [Ne] ([Ne]3s 2 3p 4 ) S + 2e S 2 [Ar] Naming Ions and Predicting Charge Isoelectronic with noble gas Section 4.1 Cations: When a metal loses electrons, it becomes a cation Add the word 'ion' after the atom name Ex. sodium sodium ion calcium calcium ion Ex. [Ar] 4s 2 [Ar] Ca Ca 2+ [Ne] 3s 2 3p 1 [Ne] Al Al 3+ [Ar] 4s 2 3d 3 [Ar] 3d 3 V V 2+ Loses 4s e...
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