bonding. bonds between atoms covalent ionic molecular substance network solids

BONDINGBONDING

Bonds Between Atoms

Covalent

Ionic

Molecular Substance

Network Solids

Ionic Bonds

•What is an Ionic Bond?

- An Ionic Bond is a chemical bond resulting from the TRANSFER of electrons from one bonding atom to another

• When is an ionic bond formed?

- An ionic bond is formed when a cation (positive ion) transfers electrons to an anion (negative ion).

Example 1

www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf -

Example 2

•Some atoms, such as oxygen, need to gain two electrons to achieve stability.

•The two electrons released by one magnesium atom could be gained by a single atom of oxygen.

•When this happens, magnesium oxide (MgO) is formed.

Magnesium Oxide 2

Calcium Chloride

Potassium Oxide

Click for Animation

Covalent Bonds•What is an Covalent Bond?

- A covalent bond is a chemical bond resulting from SHARING of electrons between 2 bonding atoms.

• What forms a covalent bond?

- A covalent bond is formed between two nonmetals.

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Examples of Covalent molecules

The neutral particle is formed when atoms share electrons is called a molecule

A molecule is the basic unit of a molecular compound.

What are some characteristics of an ionic bond?

1. Crystalline at room temperatures

2. Have higher melting points and boiling points compared to covalent compounds

3. Conduct electrical current in molten or solution state but not in the solid state

What are some characteristics of a covalent bond?

1. Covalent bonds have definite and predicable shapes.

2. Very strong

3. Low melting and boiling points

Covalent Bonds can have multiple bonds, so you should be familiar with the following…

Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms.

Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms.

Triple Covalent Bond-chemical bond resulting from sharing of three electron pairs between two atoms.

Covalent Network Structures

A covalent network is when atoms are bonded together covalently to form giant macromolecular structures.

The element Carbon can form Covalent Network structures

Two examples are:Diamond & Graphite

Diamond

Each Carbon atom bonds to 4 others

Strong covalent bonds throughout

High melting points and Boiling points

No free electrons so does not conduct electricity.

Graphite

Each Carbon atom is bonded to 3 others

The bonding within the layers is strong covalent.

The spare fourth electron of each C atom is delocalised so graphite can conduct electricity

There are weak intermolecular forces of attraction between the layers.

Covalent Networks

Another example of a covalent network is silicon dioxide. This is a compound though it resembles diamond.

Ionic VS Covalent bonding