Introduction

• Chemical Bonding – The simultaneous

(“same time”) attraction of 2 nuclei for electrons.

• Eg. H + H H2

***if attraction is strong enough, a bond forms.

Why does Bonding take place???

• 1.) All elements want 8 valence

electrons . . . to be like a Noble Gas.

(Octet Rule)

• 2.) To become MORE STABLE by releasing energy!

Types of Bonding

3 Types:

1.) Ionic Bonding

2.) Covalent Bonding

3.) Metallic Bonding

Ionic Bonding

• Ionic Bonding

– Transfer (not sharing) of electrons– Transfer from Metals Nonmetals– Salts = ionic compounds

• The greater the difference in Electronegativity (E.N.), the MORE ionic!

Q.1: Which bond is more ionic . . .NaCl or KCl???

• Q.2: Which bond is the most ionic . . .

a.) KCl b.) CaCl2 c.) MgS d.) KF

• Q.2: Which bond was the least ionic?

• HW:

Read pp.236-240. Write a ½ page Reflection.

Covalent Bonding

• Covalent Bond:– Compound formed through the sharing of

electrons between two Nonmetals (Nonmetal—Nonmetal)

– **Hydrogen (H) is included as a Nonmetal!

• Eg. Draw the electron-dot structure of

a.)H2 and b.)NaCl

• H2 NaCl

•

Covalent Bonding

• Molecule – A covalently bonded compound.

• Q: Which of the following are molecules?

a.) NaCl b.) Zn3P2 c.) CO2 d.) Al2S3

Q: Which of the above are salts?

• Q.2.: What are two differences between an Ionic bond and a Covalent bond? (see notes)

Types of Covalent Bonding

2 Types of Covalent Bonding:

• a.) Nonpolar Covalent Bonding

• b.) Polar Covalent Bonding

*** “Whoever is stronger (higher E.N.) controls the electrons the longest!”

Nonpolar Covalent BondingA.) Nonpolar Covalent Bonding: (“NO poles”)

• EQUAL sharing of electrons (link)

• Same electronegativity – (Therefore, same element)

Nonpolar Covalent Bonding (cont’d)

• Diatomic Molecules = 2 atoms of the same element covalently bonded.

Eg. H2

• ***All Diatomic Molecules: “ BrINClHOF ”

Br2 I2 N2 Cl2 H2 O2 F2

Drawing Molecules

** 1 bond = ___ electrons = ___ electron pair(s) **

Drawing Molecules (cont’d)

• Single Covalent Bond =

____electrons (___pair) are shared equally.

• Double Covalent Bond =

____electrons (____pairs) are shared equally.

• Triple Covalent Bond =

– ____ electrons (____ pairs) are shared equally.

Drawing Molecules (cont’d)

• Eg. Draw each of the following and tell if it has a Single, Double, or Triple Covalent Bond.

**Hint: Determine how many bonds

each element can form!**

1.) F2 2.) Br2 3.) O2 4.) N2

***Nonpolar Molecular shapes = LINEAR

Linear -

Polar Covalent Bonding

Polar Covalent Bonds: (2 poles)– UNEQUAL sharing of electrons b/t atoms with

different E.N.

– Eg. HF

H F (show E.N. for each)

*** δ = slight charge from unequal sharing ***

Polar Covalent Bonding (cont’d)

H F (show E.N. for each)

Q.1: Which has a slight (-) charge (δ-)?

Which has a slight (+) charge (δ+)?

δ- = δ+ =

Polar Covalent Bonds

Drawing Molecules (cont’d)

Rule for covalent bonds w/ more than 2 atoms:

***Atom (element) that needs the most electrons will be in center!***

FormulaElectron-dot

diagramShape Polar or

Nonpolar?

F2 δ- =δ+ =

HF δ- =δ+ =

CH4 δ- =δ+ =

H2O δ- =δ+ =

H3N

(NH3)

δ- =δ+ =

• HW a.): – Covalent Bond packet. Answer questions

on the last sheet (Answer sheet).

• HW b.): – Study for quiz tomorrow (Covalent

Bonding)

Formula Electron Dot structure

ShapeBond type(polar or nonpolar)

H2O

CO2

CCl4

PH3

(H3P)

Drawing Polyatomic Ions (Table E)

• All polyatomic ions on Table E are bonded covalently

• Follow SAME procedure for drawing covalent molecules

• Include a.)brackets and b.)charge (add or subtract electrons accordingly).

FormulaElectron Dot

structure Shape

Bond type(polar or nonpolar)

H3O+

CN-

SO4-2

PO4-3

Q.1: Label the following compounds as ionic, covalent, or both.

FormulaIonic, covalent, or

both? Why?

NaI

CaCO3

C2H6

NaNO3

H2

Types of Covalent Molecules

• Review:– 2 Types of Covalent Bonds:

a.) Polar b.) Nonpolar– Determined by E.N.

• 2 Types of Covalent Molecules:

a.) Polar b.) Nonpolar

– Determined by shape (symmetrical or asymmetrical)

Nonpolar Molecules

A.) Nonpolar Molecules:

1.) Symmetrical (equal distribution of

charges)

– Mirror image in both directions (make dotted lines (up/down, left/right) through center.)

• Eg. Cl2, CH4, CO2

Polar Molecules

B.) Polar Molecules:

1.) Asymmetrical (unequal distribution

of charges)

– Not a complete mirror image (one direction only)

Eg. H2O, NH3, HF

Formula Electron-dot Structure

Shape Bond Type:Polar or

Nonpolar

Molecule Type:Polar or

Nonpolar

Cl2

H2O

CO2

CCl4

NH3

Review Questions:

• Q.1: Which of the following contains the most polar bond?

a.) HF b.) HCl c.) HBr d.) HI

Review Questions: Matching

1.) Contains an ionic bond. A.) NaI

2.) Is nonpolar because all its bonds are nonpolar.

B.) O2

3.) A nonpolar molecule that contains polar bonds.

C.) NH3

4.) A polar molecule that contains polar bonds.

D.) CO2