GC Bonding.notebook

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October 21, 2011

Oct 14­7:34 AM

Chemical Bonding

Oct 14­7:36 AM

What is a chemical bond...???• a bond is made of electrons

• the electrons can be shared (covalent bonding) or transferred (ionic bonding)

• it is the valence electrons that are involved in bonding

• when two or more elements come together and bond...they form a compound

GC Bonding.notebook

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October 21, 2011

Oct 14­7:39 AM

Covalent Bonding & Compounds:

• two or more nonmetals bonded together• electrons are shared between the two atoms in the bond• Properties of covalent compounds:

low melting and boiling pointsusually do not dissolve in waterdo not conduct electricity when dissolved in water

Oct 14­8:56 AM

Naming Covalent Compounds...• name the 1st element with its periodic table name

• change the ending of the 2nd element name to "-ide"

• indicate the # of each atom with a prefix (mono = 1, di = 2, tri = 3, etc...)

• the prefix "mono" (1) is optional for the 1st element and required for the 2nd

• if there are two vowels together between the prefix and the element name - you can drop the element name vowel

Example: triiodide = triodide, monooxide = monoxide

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October 21, 2011

Oct 14­7:44 AM

Naming Covalent Compounds:

SF6

C3H8

N2O6

NO

Oct 14­8:51 AM

iodine tribromide

nitrogen trioxide

diphosphorus tetraoxide

carbon tetrafluoride

Writing Covalent Compound Formulas

GC Bonding.notebook

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October 21, 2011

Oct 14­9:01 AM

On pg # 1 in your packet at the bottom...try...

#3 SF6

#4 C3H8

#6 N2O6

#11 iodine tribromide#12 nitrogen trioxide#13 diphosphorus tetraoxide

sulfur hexafluoridetricarbon octahydridedinitrogen hexaoxide

IBr3

NO3

P2O4

Oct 14­7:52 AM

What are Lewis Structures?• Show the bonding in a covalent compound in picture form.• Bonds are represented by lines, non-bonded electrons by dots.• a bond (1 line) = 2 electrons• From the Lewis Structure you can determine the shape of the compound, which helps determine the properties of that compound.

GC Bonding.notebook

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October 21, 2011

Oct 14­7:52 AM

H Be B C N O F Ne

# valence e-

# bonds

shapes linear linear trigonal tetra- trigonal bent linear planar hedral pyramid

Lewis Dot Structures of Atoms

** Be is a metal, but still can covalently bond because of its small atomic radius.It is small enough to have its valence electrons overlap with another atom's valence electrons.

Oct 14­7:58 AM

Drawing Lewis Structures...The Rules1. Add up the total # of valence electrons in the formula.

2. Determine the central atom.the first atom listed (except for hydrogen)

or...the atom with the least number of valence electrons (except for hydrogen)

3. Bond all the other atoms to the central atom. Use lines to represent the bonds. (Remember: each bond = 2 electrons)

GC Bonding.notebook

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October 21, 2011

Oct 14­8:02 AM

4. OCTET RULE: Every atom in the structure must have 8 electrons around it.

Fill in the octets using PAIRS of electrons (dots).

Exceptions: Hydrogen (H) - 2 electrons or 1 bondBeryllium (Be) - 4 electrons or 2 bondsBoron (B) - 6 electrons or 3 bonds

5. Check:

total # electrons in picture = # valence electrons counted

The Rules Continued...

Oct 15­7:37 AM

The Rules Continued...

6. CARBON - MUST HAVE 4 bonds, no dots!!!

7. DO NOT string oxygens together O O O...

8. DO NOT make boxes C C

C C

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October 21, 2011

Oct 15­7:32 AM

Single Bond Examples:1. Cl2 2. SiF4

valence e-: valence e-:shape: shape:

Oct 15­7:34 AM

3. H2O 4. OH-1

valence e-: valence e-:shape: shape:

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October 21, 2011

Oct 15­7:35 AM

5. NH3 6. N2H4

valence e-: valence e-:shape:

Oct 15­7:36 AM

7. C3H8 8. C2H5OH

valence e-: valence e-:

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October 21, 2011

Oct 18­8:53 AM

Double & Triple Bonds

1. O2 2. N2

Oct 18­8:53 AM

3. C2I4 4. C2H5O

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October 21, 2011

Oct 15­7:45 AM

Lewis Structures for IonsPositive Ions: subtract the # of electrons in the

charge from the totalNegative Ions:add the # of electrons in the charge

to the total

PO4-3