Metals

Seite 1

Metals

1. Structure and bonding

The metallic structure is positive ions in a sea of mobile electrons.

Metals have high melting and boiling points as they have high electrostatic forces between the positive ions and the sea of mobile electrons.

Metals are malleable and ductile due to their layered structure where they can slide over each other easily.

Metals can conduct heat and electricity as they have a sea of mobile electrons which can conduct electricity.

Alloys are stronger and harder than metals as the other elements combined disrupt the layers so they are not able to slide over each other.

2. Reactivity series

The metals are arranged from most reactive to least reactive: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver.

Thermal stability decreases and ease of extraction increases down the reactivity series.

Potassium and calcium are explosive when reacted with water and diluted acid.

Calcium and magnesium reacts with water.

Aluminium reacts slowly with water but stops as a layer of insoluble aluminium oxide is formed, preventing further reaction.

Zinc and iron reacts with steam.

Lead reacts slowly with steam.

Copper and silver does not react with anything.

Calcium reacts vigorously with diluted acid.

Magnesium reacts quickly with diluted acid.

Aluminium, zinc, iron and lead reacts with diluted acid.

Potassium and sodium carbonates do not decompose while the others form CO2.

3. Extraction of iron

1. Haematite, limestone and coke enters. 2. Limestone decomposes. (Ca2CO3 --> 2CaO + CO2)

3. Coke combusts. (C + O2 --> CO2)

4. Carbon dioxide from 2 and 3 reacts with excess coke. (CO2 + C --> 2CO)

5. Iron ore reduced to iron. (Fe2O3 + 3CO --> 2Fe + 3CO2)

6. Slag is formed. (CaO + SiO2 --> CaSiO3)