Welcome to the science presentation

of Formative Assessment-3

The topic we are going to discuss now is

Metals and Non-metals

Group Members Chirag jainSanyam jainRisahbhDeepanshuAkshayTushantUttkarshSwarndeepGaurav

physical

propertie

s of

metals ...

1. Metals are malleable , that is , metals can be beaten into thin sheets with a hammer .2. Metals are ductile , that is , metals can be drawn into thin wires.

3. Metals are good conductors of heat .

4. Metals are lustrous and can be polished .

5. Metals are good conductors of electricity .

6. Metals are sonorous .

7. Metals have high densities .

Chemical Reaction of metals

Reaction of metal with oxygen

Almost all metal combing with oxygen to from metal.

For example:- Copper (Cu) reacts with oxygen to from

copper (ll) oxide , a black oxide. 2Cu + O₂ 2CuO

Metal + Oxygen Metal oxide

Aluminium (Al) reacts with oxygen to from aluminium Oxide.

4Al + 3O₂ 2Al₂O₃Sodium reacts with oxygen at room temprature

to from sodium oxide . 4Na + O₂ 2Na₂OMagnesium does not react with oxygen at room

temprature. On heating in oxygen , magnesium burns with dazzling white light to give magnesium oxide

2Mg + O₂ 2MgO

Reaction of metal with water

Metal + Water Metal oxide + Hydrogen Metal oxide + Water Metal HydroxideFor Example:- Sodium and Potassium react violently with cold

water. The reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.

2K + 2H₂O 2KOH + H₂ + Heat energy2Na + 2H₂O 2NaOH + H₂ + Heat energy

Calcium also reacts with water at room temprature forming calcium hydroxide .

Ca + 2H₂O Ca(OH)₂ + H₂ Reaction of metal with Acid When metal reacts with a dilute acid , then a metal salt and hydrogen gas are formed. Metal + Dilute acid Metal salt + Hydrogen

Example will shown in table on next slide

Metal Acid Nature of Reaction Reaction

Sodium Dil. HClDil. H₂SO₄

Sodium reacts vigorously with dil. HCl and dil. H₂SO₄

2Na + 2HCl 2NaCl + H₂2Na + 2H₂SO₄ Na₂SO₄ + H₂

Magnesium Dil. HClDil. H₂SO₄

Magnesium reacts rapidly with dil. HCl and dil. H₂SO₄

Mg + 2HCl MgCl₂ + H₂Mg + H₂SO₄ MgSO₄ + H₂

Zinc Dil. HClDil. H₂SO₄

Zinc reacts with dil.HCl and dil. H₂SO₄ at moderate rate .

Zn + 2HCl ZnCl₂ + H₂Zn + H₂SO₄ ZnSO₄ + H₂

Iron Dil. HClDil. H₂SO₄

Iron reacts with dil.HCl as well as Dil. H₂SO₄ slowly at room temprature.

Fe + 2HCl FeCl₂ + H₂Fe + H₂SO₄ FeSO₄ + H₂

Copper Dil. HClDil. H₂SO₄

Copper does not react with dil. HCl and dil. H₂SO₄slowly at room tempratureBut slowly dissolve in dil. H₂SO₄ in the presence of air.

No reaction

2Cu + 2H₂SO₄ + O₂ 2CuSO₄ + H₂O

Reaction of metal with salt solution

A less reactive metal is displaced from its salt solution by a more reactive metal.Reaction of zinc with copper sulphate solution When a strip of zinc metal is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually due to the formation of colourless zinc sulphate, and red-brown copper metal is deposited on the zinc strip:

CuSO₄ + Zn ZnSO₄ + Cu

Reaction of metals with Chlorine

Metals react with chlorine to from ionic chlorides. For example:-Sodium is a metal. So, sodium reacts with

chlorine to from an ionic chloride called sodium chloride:

2Na + Cl₂ 2NaCl Calcium is a metal which reacts vigorously with

chloride called calcium chloride:Ca + Cl₂ CaCl₂

Reaction of metal with hydrogenOnly few reactive metal like sodium, potassium, calcium, and magnesium reacts with hydrogen to from metal hydrides. For example: When hydrogen gas is passed over heated

sodium then sodium hydride is formed :2Na + H₂ 2NaH

When hydrogen gas is passed over heated calcium then calcium hydride is formed:

Ca + H₂ CaH₂

Chemical properties of non metal

Reaction of non-metals with oxygen

Non-metals react with oxygen to form acidic oxides or neutral oxides . The acidic oxides of non-metals dissolves in water to form acids .

C (s) + o₂ - co₂ Carbon oxygon carbon dioxide

CO2 (g) + H2O (l) – H2CO3 (aq)

carbon dioxide water carbonic acid

Reaction of non-metals with water

• Non-metals do not react with water to evolve hydrogen gas . This is because non-metals cannot give electrons to reduce the hydrogen ions of water into hydrogen gas

Reaction of non-metals with dilute acids

Non-metals do not react with dilute acids . Non-metals do not displaces hydrogen from acids . Non-metals like carbon , sulphur or

phosphorus are put into a test tube containing dilute sulphuric acid or dilute

hydrochloric acid , then no hydrogen gas is evolved .

Reaction of non-metals with salt solutions

A more reactive non-metal displaces a less reactive non-metal from its salt solution.

2NaBr (aq) + Cl2 (g) - Br2 (aq) + 2NaCl (aq) Sodium chlorine bromine Sodium

Bromide chloride

Reaction of non-metals with chlorine

Non-metals react with chlorine to form covalent chlorides which are non-electrolytes

(do not conduct electricity )H2 (g) + Cl2 (g) - 2HCl (g)

Hydrogen chlorine hydrogen chloride

(non-metal) (covalent hydride)P4 (s) + 6Cl2 (g) - 4PCl3 (l)

(non-metal) (covalent hydride)

Reaction of non-metals with hydrogen

Non-metals react with hydrogen to form covalont hydrides

H2 (g) + S (l) - H2S (g)

Hydrogen sulphur hydrogen sulphide

(non-metal) (covalent hydride)

N2 (g) + 3H2 (g) - 2NH3 (g)

Nitrogen hydrogen ammonia

(non-metal) (covalent hydride)

Ionic compounds

The compounds containing ionic bonds are called ionic compounds.Theyare formed by transfer of electrons from one atom to another . Ionic compounds are made up of positively charged ions[cataions]+ and negatively charged ions [anions].Ionic compounds are also known as Electrovalent compounds.

Some common ions

Structure of ionic copounds

The forces between the particles are strong.There are no free-moving electrons present, unlike in metals.There are charged particles present, but in solid state they are not free to move. When an ionic compound melts, however, the particles are free to move and the compound will conduct electricity.

Electron Dot Structure or Lewis Dot Diagram

A notation showing the valence electrons surrounding the atomic symbol.

Elements within same groups have same electron dot structure

PROPERTIES OF IONIC COMPOUNDS

IONIC COMPOUNDS

1 THESE COMPOUNDS ARE USUALL CRYSTALLINE SOLIDS . BECAUSE THEIR OPPOSITELY RGED IONS

ATTRACT EACH OTHER.THESE IONIC COMPOUNDS ARE HARD AND

BRITTLE . IONIC COMPOUNDS HAVE HIGH MELTING AND HIGH BOILING POINT. EX – SODIUM CHLORIDE HAS HIGH MELTING POINT.

SOME IMPORTANT POINTS ON

IONIC COMPOUNDSIONIC COMPOUNDS CONDUCT

ELECTRICITY WHEN DISSOLVED IN WATER. THERE

ARE PLENTY OF FREE IONS IN SOLUTION WHICH ARE ABLE TO CONDUCT

ELECTRICITY. EX-ACETONE,KEROSENE etc.

•EXPERIMENT- SODIUM

CHLORIDE HEATED ON A

SPATULATAKE A SMALL

AMOUNT OF SODIUM CHLORIDE ON METAL

SPATULA . HESTED OVER A FLAME OF BURNER SODIUM CHLORIDE

MELTS ONLY ON STRONG HEATING THIS SHOWS THAT SODIUM

CHLORIDE HAS A HIGH MELTING POINT

EXPERIMENT- SODIUM

CHLORIDE CONDUCTS

ELECTRICITYFILL A BEAKER HALF WITH

WATER AND DISSOLVE SOME SODIUM CHLORIDE IN IT. TWO

CARBON AND ELECTRODES ARE PLACED IN IT. AN ELECTRIC

SWITCH IS SET UP BY INCLUDING BATTERY BULB AND

SWITCH. ON PRESSING THE SWITCH BULB LIGHTS UP . THIS

MEANS THAT THE SOLUTION TAKEN IN THE BEAKER IS ALLOWS TO CONDUCT

ELECTRICITY. SINCE SODIUM CHLORIDE IS AN IONIC COMPOUND CONDUCT

ELECTRICITY WHEN DISSOLVE IN WATER.

Corrosion :-Corrosion :- The surface of some metals gets corroded when exposed to moist air for a long time. This is called corrosion. Prevention of corrosion of metals :- The corrosion of metals can be prevented by: i) Applying oil or grease. ii) Applying paintiii) Galvanisation ( coating of metals with non corrosive metals like zinc)iv) Electroplating ( coating of metals with non corrosive metals like chromium tin by passing electricity) v) Alloying ( Eg. When iron is alloyed with chromium and nickel, it forms stainless steel which is resistant to corrosion)

An alloy is a homogeneous mixture of a metal with other metals or non metal.

An alloy is a homogeneous mixture of a metal with other metals or non metal.

Alloy Constituents Uses Steel iron, carbon construction of tools, machines, tanks, vehicles, ships, rails, building, bridges, dams etc. Stainless steel iron, chromium utensils, cutlery, surgical instruments etc. Brass copper, zinc utensils, handicrafts musical instruments etc. Bronze copper, tin statues, medals, bells ornament

Alloys :

Why alloys are made?

Alloys are stronger than the metals from which they are made.

Alloy are harder than the constituent metals.Alloy are more resistant to corrosion.Alloy have lower melting points than the

constituent metals.Alloys have lower electrical conductivity than

pure metals.

Questing

A. The most abundant metal in the earth’s crust is: aluminium

B. The constituent of stainless steels are: Iron,nickel,chromium

C. For iron to rust : both air and water are necessary

D. Amalgam is an alloy of one or more metal: mercury