Chapter 7 Notes Book chapter 5 Video #18

7-1 Chemical Bonding -Atom: basic building block of matter -114 elements (video #19, 20) *Chem bonding: combining of atoms of elements to form new substances

-Electrons and nrg Levels -2,8,8 *Valence e-: -Stable vs Nonstable

Ex’s

-Electrons and Bonding -e- in the outermost nrg level determines whether or not the atom will form chem bonds.

7-2 Ionic Bonding *Ionic bonding: transfer of e- *Ion: charged particle - Gaining or losing of e- - + or - atoms - Electromagnetic force hold opp charges together

-Ionization nrg and Electron Affinity *Ionization: 1. Nrg needed to remove e- 2. Ionization nrg for atoms with many e-, is high 3. Atoms with few e-, is low

Ion ex:

NaCl--everyone is happy

*Electron Affinity: tend to attract e-

-Arrangement of Ions in Ionic Compounds *Crystal lattice: regular repeating arrangement -gives great stability -accounts for certain physical properties ex: ionic cmpnd high MP

-Each ionic cmpnd has a characteristic crystal lattice

-Ionic Properties -rigid crystal -conduct elect when melted or dissolved in H2O -probably a metal and nonmetal (from groups 16 or 17) -high melting points

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7-3 Covalent Bonds *Cov Bon: sharing of e- -between atoms that have high ionization nrg and high electron affinities(Neither atom loses e- easily)

Ex

Covalent bonds form between: 2 nonmetals or a nonmetal and hydrogen

Covalent or ionic? Na and Cl ionic C and H covalent C and S covalent Ca and S ionic

-Nature of the Covalent Bond -Simplest is between H atoms *Electron-Dot Diagram: show only valence e- Ex’s: *Diatomic elements: always exist as 2 atoms cov. bonded

-Formation of Molecules *Molecule: combination of atoms formed by a cov. Bond. -smallest part. Of a cov bonded substance that has all the prop. of that substance

-Cov bonded solids tend to have low mp. *network solids: -high mp -large molecules -atoms continue to bond to one

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-Polyatomic ion *group of covalently bonded atoms that act like a single atom when combining with other atoms ex: NH 4

Compounds containing polyatomic ions are named by using your polyatomic ion chart.

7-4 Metallic Bonds *outer e- of the atoms form a common e- cloud -sea of mobile e- accounts for many of the properties of metals ex: malleable, ductile

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-metal ions can slide by each other and the e- are free to flow -also accounts for the high electric conductivity and high MP

7-5 Predicting Types of Bonds -Compounds formed between elements that lose e- easily and those that gain e- easily will have ionic bonds. ex: metal and a nonmetal

-Compounds formed between elements that tend to gain e-’s will have covalent bonds. ex: between nonmetals ?MgF; OCl; KCl; SBr; CaS

-Combining Capacity of Atoms *Oxidation #: -some elements have more than one oxidation #; it depends on the other atoms with which it bonds

-Using Oxidation # -Use to predict how atoms will combine and what the formula for the resulting cmpnds will be. ~the sum of the ox must = 0 EX’s: