Lesson 26

Electron Glue

Bonding

Chemical Bond - an attraction between atoms that holds them together in space

• Different electron locations give different properties to substances

Ionic Bonding - type of chemical bond that is the result of transferring of electrons from one atom to another

IONIC

Properties of ionic substances:

Dissolve in water

Conduct electricity when dissolved

Tend to be brittle solids

Made of metal and nonmetal atoms combined

In ionic bonding, the valence electrons are transferred from one atom to another. Metal atoms transfer their valence electrons to nonmetal atoms.

Covalent Bonding - type of chemical bond where one or more pairs of valence electrons are shared between the atoms

MOLECULAR COVALENT

Properties of molecular covalent substances:

Some dissolve in water, some do not

Do not conduct electricity

Some are liquids or gases

Made entirely of nonmetal atoms

In molecular covalent bonding, the valence electrons are shared between pairs or groups of atoms. This creates small stable units, called molecules, within the substance.

NETWORK COVALENT

Properties of network covalent substances:

Do not dissolve in water

Do not conduct electricity

Extremely hard solids

Made entirely of nonmetal atoms

Network covalent bonding is similar to molecular covalent bonding, but the valence electrons are shared throughout the entire substance.

Metallic Bond - bond between metal atoms where the valence electrons are free to move throughout the substance

METALLIC

Properties of metallic substances:

Do not dissolve in water

Conduct electricity

Bendable, malleable solids

Made entirely of metal atoms

In metallic bonding, the valence electrons are free to move about the substance.

Molecule - a group of atoms covalently bonded together

    Metal Atoms      Nonmetal Atoms      Metal & Nonmetal

|                     |              |                          |

|                     |              |                          |

\/                    \/            \/                         \/

Metallic       Network  Molecular            Ionic

Practice Problems

3. a) metallic
    b) molecular covalent
    c) ionic
8. Copper is used as wire because as a solid it conducts electricity but copper chloride as a solid does not conduct.

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