Warm-Up #27 A. 40 1.Ionic bonds form between a metal and another metal. T / F 2.A bond between two nonmetals is called a covalent bond. T / F 3.Ionic compounds.

Warm-Up #27 A. 40

1. Ionic bonds form between a metal and another metal. T / F

2. A bond between two nonmetals is called a covalent bond. T / F

3. Ionic compounds have a low melting point. T / F

4. Draw the Lewis dot structure for F.

5. Draw the Lewis dot structure for Li.

Warm-Up # 28 A. 41

• Complete the chart

Warm-UP #29 Copy and Answer

1. Group 1 has two valence electrons. T / F

2. Group 13 has thirteen valence electrons. T / F

3. Group 18 has 8 valence electrons. T / F

4. What is the Lewis dot structure for Be?

5. What is the Lewis dot structure for P?

Covalent Bonding

Remember…

• Ionic bonds forms between metals and nonmetals.

• An ionic bond happens when one atom transfers its valence electron(s) to another atom.

Covalent Bonding

• What are covalent bonds?– A covalent bond forms when atoms share one or

more pairs of valence electrons.– Covalent bonds form between a nonmetal and

another nonmetal.

How to Represent Covalent Bonds

• Let’s consider H2, the simplest molecule.

• What is the Lewis dot structure for Hydrogen?

• Use the Lewis dot structure to show two Hydrogen atoms combining.

H•

hydrogen atom

H•

hydrogen atom

+ •H

hydrogen atom

H•

hydrogen atom

+ •H

hydrogen atom

H H

hydrogen molecule

•

•

Shared pair of electrons

How to Represent Covalent Bonds Cont.

• What would the product of the two Hydrogen atoms look like?

• Use Lewis dot structures to show the entire reaction

H H

hydrogen molecule

•

•

• • F•

• ••

atom

• • •

• • F • •

atom

•+ F F ••

•

•

••

• • • •

• • • •molecule

or••

structural formula

••

• • • •

• • • •F - F

shared pair

Covalent Bonding

• Show the reaction of two Fluorine atoms combining to create F2.

Can atoms share more than one pair of electrons?

• YES!!!• Atoms sometimes share more than one pair of

electrons to attain 8 electrons.• Double covalent bonds involve two shared pairs

of electrons.

Covalent Compounds

• Most items around you are covalently bonded such as water, sugar, oxygen and cellulose in wood– What are some other covalently bonded

things?

• Properties of Covalent Compounds– Brittle Solids– Low melting and boiling points

Covalent Compounds Cont.

• Covalent compounds frequently involve more than two atoms combining.– Water, H2O

– Methane, CH4