Reactions of Metals with O2

Metal Reaction rate

Product of reaction

Magnesium Very fast Magnesium oxideAluminium Very fast Aluminium oxideZinc Fast Zinc oxideIron Fast Iron oxideCopper Slow Copper oxide

Reactions of Metals with Sulphur, S

Metal Reaction rate

Product of reaction

Magnesium Very fast Magnesium sulphideAluminium Very fast Aluminium sulphideZinc Fast Zinc sulphideIron Fast Iron sulphideCopper Slow Copper sulphide

Sand is an example of SILICON

SILICON

• Shiny• Bluish - grey• Brittle metalloid with a high melting point• It looks like a metal but it is Chemically more like a non-metal.

appearance

• Stable compounds• Insoluble in water• Do not decompose on heating• Do not react with acids

propertiescompounds

• Does not occur freely in nature.

• silicon usually combines with other elements like metals and oxygen to form: - SILICA AND SILICATE.

1

2

3

6.3 Silicon Compounds

6.3 Silicon Compounds

• Silicon is the second most abundant element in the Earth’s crust.

• Silicon does not exist as a free element in its natural state, but in compounds

• Silicon compounds in the Earth’s crust – silica, silicates

silicon dioxide

Silicates– silicon, metal, oxygen

Silicon compounds and their examples

Silicon compound

Example

Silica Sand, quartzSilicate Asbestos, jade, clay, mica

Asbestos

Jade

Clay

Mica

Silica and Silicates

• Insoluble in water• Do not react with acid• Do not break down when heated• That’s why they are very stable in the

Earth crust• Hence, not easily eroded, found in large

quantities in the Earth’s crust

Silica and Silicates

• In industry:– Manufacture of glass, fiber optic cables,

ceramics

ceramics

SILICA

• Also known as silicon dioxide.

• it is combination of: silicon + oxygen silicon dioxide ( silica)

• Example of silica are:

1. Sand – used to make bricks, mortar, cement, concrete and glassware like flasks and mirror.

2. Flint- used to light lighter and gas stove

3. Quartz- strong and transparent , used for making watches and prisms.

SILICATE

1. It is combination of :

Silicon + oxygen + metal silicate

• Example of silicate are:• Clay - use to make ceramics goods like flower pots and pottery.• Mica - use as an electric insulator in electrical equipment• Asbestos - used as heat insulators in the form of sheets like fire-fighters outfits.• Jade, Ruby and Topaz - used as ornamental stones because these silicate have very beautiful colour.

sand Rock crystal Mica Asbestos Topaz

Flint Opal Clay Jade Ruby Feldspar

Uses of silicon compounds in daily life:

Used as ornamental stones