Chemical Bonding

1. Covalent bonding

2. Ionic bonding

All elements and atoms need stability.

Ionic Bonding

This occurs when electrons are transferred.

Reacting sodium (Na) with chlorine (Cl):

Ionic Bonding

This occurs when electrons are transferred.

Metal atoms lose the electron, or electrons, in their highest energy level and become positively charged ions. Non-metal atoms gain an electron, or electrons, from another atom to become negatively charged ions.

The force of attraction between these oppositely charged particles keeps them together. This occurs between metals and non-metals.

Patterns

Group 1 +1 Na+

Group 2 +2 Mg2+

Group 3 +3 Al +

Group 4 Share electrons

Group 5 -3 N-3

Group 6 -2 O-2

Group 7 -1 Cl-3

Group 0 Unreactive

http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/atomic/

Group 1 elements react with elements in group 7.

Group elements lose an electron and group 7 elements gain an electron.

Covalent bonding

This occurs when electrons are shared. These occur between non-metals.

Example 1

Water

Example 2

Oxygen

Oxygen AtomOxygen Atom Oxygen AtomOxygen Atom

Oxygen Molecule (O2)

Example 3

Chlorine

Use your periodic tables and knowledge of electron arrangements to answers the following questions:

1. Why are group 7 elements (halogens) so reactive?

2. Why are group 0 elements (noble gases) so un-reactive?

3. Draw the ions that would be formed for the following:

Aluminium (Al) Potassium (K) Fluorine (F) Oxygen (O)

For each state whether electrons had been lost of gained.

4. Complete the following table:Atomic number

Atom Electronic structure of

atom

Ion Electronic structure of ion

8 O [2,8]2-

19 2,8,8,1 K+

17 Cl Cl-

20 2,8,8,2

5. Draw dot and cross diagrams to show how the following to form ions together:- lithium and chlorine- calcium and oxygen- aluminium and chlorine

6. Draw diagrams to show the covalent bonds between the

following atoms:

- 2 hydrogen atoms- 2 chlorine atoms- a hydrogen and a fluorine atom