Chemistry GCSE unit 2 principle of chemistry B

Ionic = Metal + Non-metal

Covalent = Non metal + Non-metal (Gaint molecule or Simple molecule)

Metallic = Metal + Metal

Positive Ions + tend to form by metal as they need to lose electron to become stable.

Negative ions - tend to form non metals as they need to gain a electron.

In order to achieve stability elements will react together to form compounds. Ionic bonding is the electrostatic attraction between oppositely charged ions.

When atoms bond only the outmost shell is involved.

 Covalent bonds are between atoms of non-metal and non-metals. The bonds form when elements share – electrons to become energitacally more stable.

 Convalent subtances can either be solids liquid or gasses.

Gasses

§  Molecules are far apart

§  Almost no forces of attraction between them.

Liquids

§  There are forces of attraction between the molecules. In some this attraction is so strong that it makes a solid.e.g ice