Bond Types

What you already know… 2 Bond types: –Ionic Steal/give electrons Makes a + and – ion Metal and nonmetal Ions are attracted like a magnet –Covalent Sharing electrons 2 non-metals Lewis dot structures Pretty good. But… there’s more to the story…

What’s new? There are really 5 types of bonds –Nonpolar covalent & Polar covalent –Ionic –Metallic –Network covalent There are bonds inside molecules (inTRAmolecular bonds) and between molecules (inTERmolecular bonds)

Covalent Covalent compounds are really the only ones with separate molecules (stay tuned) Covalent= –strong within the molecule –but weak between molecules Covalent= sharing, but not always equally…

Polar Polar bonds are sharing electrons, but NOT equally. One element has more of them See page 460

Covalent (cont.) Non-polar covalent shares electrons (mostly) equally –Forces between molecules are weak –Melting points are low (oxygen = -218 o C) Polar covalent does not share equally –Making one side  + and one  - –Molecules are attracted to each other –Forces between molecules are stronger –Melting points are higher (water = 0 o C)

Ionic Ionic= violent!! Give/Take of electrons Then, +/- attract to make a neutral atom

Ionic (cont.) Ions combine to make very strong “lattice” of attraction Makes crystals, with distinct shapes Melting points o C

Metallic Bonds with a “sea of electrons” Strong! Melting points around 1500 o C Conductive and malleable (bendable) thanks to the “sea”

Network Covalent Examples: diamond, graphite, bucky balls Strongest of them all Melting points in the range of 3000 o C ++ Each carbon (or silicon) bonds with 3-4 others

Fullerenes

Summary… Metal(s) Metal + non-metal 2 non-metals Iron, Copper… H 2 O, NH 3, PCl 3, CH 3 Cl I 2, NO 2, CH 4 Melted or aqueousnone 0.5 to 2.0 (or unbalanced structure) <0.5 Sea of e - Give/take of e - then electrostatic Sharing e - equally solid liquidgas

Did you get that? 1.Something with strong bonds (between molecules), has a high ___________ point 2.If electrons are shared unequally, the bond is ___________ 3.The strongest type of bond is __________ ___________ 4.The best conductors have _______ bonds 5.In _________ bonds electrons are swapped, not shared 6.A bond between 2 non-metals is ________ 7.Something that’s a gas at room temp, probably has _________ bonds