Metals & non- metals

Physical Properties of metals (7)

Physical Properties of metals (7)

1. Hard

2. Lustrous

3. Malleable

4. Ductile

5. Good conductors of heat

6. Good conductors of electricity

7. Sonorous

Lustre

Shine

Malleable

can be beaten into thin sheets

Ductility

can be drawn into thin wires

Sonorous

Can produce sound on striking hard surface

Chemical properties of metals

1. High melting point

Metal + Oxygen

Metal Oxide

2Cu + O₂

2CuO

4Al + 3O₂

Al₂O₃

Amphoteric oxides definition

Metal oxides which upon reacting with either acid or base, give salt and water.

Example of amphoteric oxide

Al₂O₃ and ZnO

Al₂O₃ with base

Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O

Al₂O₃ with acid

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O

ZnO with acid

ZnO + 2HCl → ZnCl₂ + H₂O

ZnO with base

ZnO + 2NaOH →Na₂ZnO₂ + H₂O

Most Metal Oxides are _______ in water.

Insoluble

Soluble metal oxides dissolve in water to form ________.

Alkalis

Sodium Oxide + Water →

Na₂O + H₂O → 2NaOH

Potassium Oxide + Water →

K₂O + H₂O → 2KOH

How do potassium and sodium react with oxygen?

They react vigorously and catch fire.

What is done to prevent Potassium and Sodium from catching fire?

They are kept immersed in kerosene oil.

What happens to copper when it is burnt?

Copper doesn’t burn but reacts with oxygen to form copper (II) oxide.

Does Iron or iron filings burn?

Iron does not burn but iron filings burn vigorously in flame.

______ and _______ do not react with Oxygen at any temperature.

Silver and Gold

What prevents metals such as zinc, lead, aluminium, magnesium, etc. from further corrosion?

The oxide layer that is formed by reacting it with oxygen prevents further oxidation.

What is Anodising?

Process of forming thick oxide layer on Aluminium.

What is taken as anode in Anodising?

Aluminium

What electrolyte is used for anodising?

Diluted H₂SO₄- Sulphuric Acid

What gas is evolved during anodising?

Oxygen gas is evolved at the anode which reacts with copper to make thicker Oxide layer.

Metal + Water →

Metal Oxide + H₂

Metal Oxide + Water →

Metal hydroxide

Which metals react vigorously with cold water?

Potassium, Sodium

What happens when Potassium and sodium react with water?

They produce so much heat that the evolved H2 catches fire.

2K + H₂O →

2KOH + H₂ + Heat

Na + H₂O →

NaOH + H₂ + Heat

What happens when calcium reacts with water? With Equation.

Exothermic reaction but less violent. Calcium starts floating because Hydrogen bubbles stick to surface of the metal.

Ca + H₂O → Ca(OH)₂ + H₂

The metal which only reacts with hot water?

Magnesium

Which metals only react with steam?

Aluminum, Zinc, Iron

2Al + 3H₂O (g) →

Al₂O₃ + 3H₂

3Fe + 4H₂O (g) →

Fe₃O₄ + 4H₂

Which metals do not react with water at all?

Copper, Silver, Gold, Lead

Which acid does not give H₂ on reacting with metal?

HNO₃- Nitric acid

What happens when HNO₃ is reacted with metals and why?

HNO₃ reacts with metals to form Salt and Water because it is a string oxidising agent and oxidises H₂ and forms water.

The 2 metals which react with HNO₃ to form H₂

Mg and Mn react with very dilute HNO₃ to form H₂ gas.

Aqua Regia composition and what can it dissolve?

HCl and HNO₃ in ratio 3:1. It can dissolve Gold and Platinum.

List Reactivity series

1. K

2. Na

3. Ca

4. Mg

5. Al

6. Zn

7. Fe

8. Pb

9. H

10. Cu

11. Hg

12. Ag

13. Au

14. Pt

Define Reactivity of elements

A tendency of elements to attain completely filled valance shell.

Ionic compounds are

Compounds formed by donating of electron(s).

Properties of Ionic compounds: (4)

• Solid state since they have strong force of attraction.

• High melting and boiling points

• Soluble in water, insoluble in kerosene and petrol.

• Conduct electricity in molten state

Define Ore.

A mineral which contains a high percentage of a metal that can be profitably extracted is called Ore.

How are highly reactive metals extracted?

1. Electrolysis of molten ore. Mostly occurs as chloride compound.

• Cathode → metal

• Anode → Chlorine

2. Purification

How are medium reactive metals extracted?

• Carbonate ore → Calcination

• Sulphide ore → Roasting

2. Reduction of oxide

3. Purification

Calcination and Roasting meaning.

• Calcination → Heating in absence of oxygen.

• Roasting → Heating in presence of oxygen

Gangue Particles meaning

The impure substances in ores like Sand, Soil, etc.

Cinnabar

Sulphide ore of mercury

Extraction of Mercury equations

2HgS + 3O_{2 + heat} → 2HgO + 2SO₂

2HgO + heat → 2Hg + O₂

Extraction of Copper

2Cu₂S + 3O_{2 + heat}→ 2Cu₂O + 2SO₂

2Cu₂O + Cu₂S + heat → 6Cu + SO₂

Calcination example

Roasting example

2ZnS + 3O₂ + Heat → 2ZnO + 2SO₂

What reaction is used to join railway tracks?

Thermit reaction:

Fe₂O₃ (s) + 2Al (s) → 2Fe (l) + Al₂O₃ (s) + heat

Electrolytic refining of metals:

Impure metal- Anode

Pure metal- Cathode

Alloy of Iron and Nickel/ Chromium

Stainless steel

What is added to iron to make it stronger?

Carbon

What is gold alloyed with?

Copper or silver

What is an alloy of mercury called?

Amalgam

Alloy of Cu and Zn

Brass

Alloy of Cu and tin

Bronze

Alloy of Lead and Tin

Solder