Metals

Июль 30, 2022

Содержание

2. Lecture Plan: Metal definition Categories of various metals The structure of metal. Metallic bond Properties of
3. OBJECTIVES: Understand the physical properties of metals. Explains the chemical properties of metals. Explain how the
4. A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material (an element, compound, or
6. Metallic Elements: Alkali metals (group IA): Li, Na, K, Rb, Cs, Fr Alkali earth metals (group
7. Metallic Elements: 4) Post-transition metals: Al, In, Ga, Sn, Tl, Pb, Bi, Po 5) Lanthanides 6)
8. The metallic bond causes many of the traits of metals, such as strength, malleability, ductility, luster,
9. In a piece of metal, all the atoms lose their outer electrons to gain full shells,
10. REASONS: GIVE 3 REASONS WHY TUNGSTEN IS USED TO MAKE THE FILAMENT INSIDE AN ELECTRIC BULB?
11. PHYSICAL PROPERTIES OF METALS Good electrical and heat conductors. Malleable - can be beaten into thin
12. Density of Metals Light metals Heavy metals Magnesium 1,74 g/cm3 Lead 11,3 g/cm3 Gold 19,3 g/cm3
13. Melting point metals Refractory metals Fusible metals
14. Metals have luster. This means they are shiny. Ductile metals can be drawn into wire. Malleable
15. A chemical property of metal is its reaction with water and oxygen. This results in corrosion
16. These properties make metals most useful in daily life.
18. CHEMICAL PROPERTIES OF METALS Usually have 1-3 electrons in their outer shell. Lose their valence electrons
19. Reactivity series of metals The arranging of metals in the decreasing order of their reactivity is
20. Use the reactivity series to predict if a reaction will take place and how intense the
21. Reaction with oxygen : Metals react with oxygen to form metal oxides: 2Cu + O2 =
22. Reaction of metals with water Those metals staying above hydrogen in electrochemical series react with cold
23. K, Na, Li and Ca react violently with dilute H2SO4 and dilute HCl, forming the metal
24. Reaction with Concentrated Acids: HNO3 and H2SO4 Hydrogen gas is not evolved when metals react with
25. Reaction with HNO3 Concentrated acid does not affect at the metals, they are passivates Cr, Fe,
26. Explaining displacement reactions The reactivity series can be used to predict if a metal will react
27. Reaction of metals with metal salt solutions and oxides A displacement reaction is one where a
28. Displacement reaction Zinc displaces copper from copper sulfate solution: Zn + CuSO4 ZnSO4 + Cu Iron
29. The more reactive aluminium takes the oxygen from the less reactive iron. The reaction gets so
30. Occurrence of metals : Some metals like gold, silver, platinum etc are found in the free
31. Occurrence of metals in nature High active metals Medium active metals Passive, noble or precious metals
32. Extraction of metals from their ores : The various processes involved in the extraction of metals
33. Ways of Metal Extraction Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminium Al Zinc Zn
34. Steps involved in the extraction of metals from their ores Metals of Metals of Metals of
35. Using of Metals Metal used in manufacturing are usually alloys, which are composed of two or
36. Ferrous Metals (black): Ferrous metals are based on iron: the group includes steel and cast iron.
37. METALS ALLOYS An alloy is a homogeneous mixture of a metal with other metals or non
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Lecture Plan:
Metal definition
Categories of various metals
The structure of metal. Metallic bond
Properties

of metals: physical, chemical
Extraction of metals
Applications and role of metals. Alloys

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OBJECTIVES:
Understand the physical properties of metals.
Explains the chemical properties of metals.
Explain

how the reactivity of metals changes across the periodic table.

List out the uses of metals and alloys.

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A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a

material (an element, compound, or alloy) that is typically hard, opaque, shiny, and has good electrical and thermal conductivity.
In chemical reaction: "Metals are the elements which form positive ions by losing electrons.“ They are also known as electropositive elements.
Metals are generally malleable — that is, they can be hammered or pressed permanently out of shape without breaking or cracking — as well as fusible (able to be fused or melted) and ductile (able to be drawn out into a thin wire).
About 91 of the 118 elements in the periodic table are metals (some elements appear in both metallic and non-metallic forms).

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Metallic Elements:
Alkali metals (group IA): Li, Na, K, Rb, Cs,

Fr
Alkali earth metals (group IIA): Be, Mg, Ca, Sr, Ba, Ra
Transition metals (Group 3 – 12, d-elements): Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Os, Hg, Pt, Au, W
Iron Triad (Group 8, 9,10): Fe, Co & Ni = They create the magnetic field
Coinage Metals (Group 11): Cu, Ag, Au = They are used to make coins.

copper

silver

gold

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Metallic Elements:
4) Post-transition metals: Al, In, Ga, Sn, Tl, Pb, Bi,

Po
5) Lanthanides
6) Actinides
7) Elements which are possibly metals: meitnerium, darmstadtium, roentgenium, ununtrium, ununpentium, livermorium, ununseptium
8) Elements which are sometimes considered metals: Ge, As, At, Sb

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The metallic bond causes many of the traits of metals, such

as strength, malleability, ductility, luster, conduction of heat and electricity.

Metallic bonding is the force of attraction between valence electrons and the metal positive ions.

Metallic Bonding

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In a piece of metal, all the atoms lose their outer

electrons to gain full shells, and become positive ions. These negative “sea of electrons” move around between the metal ions. The negative electrons attract the positive ions, making the structure strong.
Metals are good at conducting electricity and heat because of the free electrons which are able to move around.

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REASONS:
GIVE 3 REASONS WHY TUNGSTEN IS USED TO MAKE THE FILAMENT

INSIDE AN ELECTRIC BULB?

1) Tungsten can be drawn into very thin metal wires.

2) Tungsten has the highest melting point (3422°C).

3) Tungsten has strong resistance to high temperature.

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PHYSICAL PROPERTIES OF METALS
Good electrical and heat conductors.
Malleable - can be beaten

into thin sheets.
Ductile - can be stretched into wire.
Metals have a high melting point. They are also very dense.
Possess metallic luster.
Opaque as thin sheet.
Solid at room temperature (except Hg).

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Density of Metals
Light metals Heavy metals
Magnesium
1,74 g/cm3
Lead
11,3 g/cm3
Gold
19,3 g/cm3
Osmium
22,5 g/cm3
Lithium
0,53 g/cm3
Light

metals have density less than 5 g/cm3

Heavy metals have density greater than 5 g/cm3

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$Melting point metals Refractory metals Fusible metals$

Melting point metals
Refractory
metals
Fusible metals

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Metals have luster. This means they are shiny.
Ductile metals can be

drawn into wire.

Malleable metals can be hammered into sheets

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A chemical property of metal is its reaction with water and

oxygen. This results in corrosion and rust:
Me + O2 = MexOy
Me + [O] + H2O = Me(OH)n

The ability of metals to produce a particular sound when it is tapped on a hard surface is termed sonority.

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These properties make metals most useful in daily life.

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CHEMICAL PROPERTIES OF METALS
Usually have 1-3 electrons in their outer shell.
Lose

their valence electrons easily.
Form oxides that are basic.
Are good reducing agents
Have lower (EN<1,5) electronegativities.

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Reactivity series of metals
The arranging of metals in the decreasing order

of their reactivity is called reactivity series of metals:
K - Potassium
Na - Sodium Most
Ca - Calcium reactive
Mg - Magnesium
Al - Aluminium
Zn - Zinc Reactivity
Fe - Iron decreases
Pb - Lead
H - Hydrogen
Cu - Copper
Hg - Mercury Least
Ag - Silver reactive
Au - Gold

The activity series of metals is an empirical tool used to predict products in displacement reactions and reactivity of metals with water and acids in replacement reactions and ore extraction.

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Use the reactivity series to predict if a reaction will take

place and how intense the reaction will be:

acid

gold

metal

reacts with

calcium

sodium

oxygen

silver

prediction

zinc

water

no reaction

fizzing

burns vigorously

very slow reaction

burns moderately

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Reaction with oxygen :

Metals react with oxygen to form metal oxides:
2Cu

+ O2 = 2CuO – Q
4Al + 3O2 = 2Al2O3 – Q
4Na + O2 = 2Na2O + Q
The most reactive metals as K, Na, Li, Ca and Mg react with oxygen and burn in air.
Metals from Al to Cu in the activity series of metals, react slowly when heated in air to form the metal oxides. Aluminium is the fastest and copper is the slowest of them.
Iron metal does not burn in dry air even on strong heating. In moist air, iron is oxidized to give rust:
Gold and platinum do not react with oxygen in air.

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Reaction of metals with water
Those metals staying above hydrogen in electrochemical

series react with cold water or steam to produce hydrogen:
Active metals at room temperature are formed hydroxides:
Medium active metals at high temperature with steam are formed oxides:
Sn, Pb, Cu, Ag, Au and Pt do not react with water or steam.

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K, Na, Li and Ca react violently with dilute H2SO4 and dilute

HCl, forming the metal salt (either sulfate or chloride) and hydrogen gas:
Zinc with dilute sulphuric acid is often used for the laboratory preparation of hydrogen. The reaction is slow at room temperature, but its rate can be increased by the addition of a little copper (II) sulphate. Zinc displaces copper metal, which acts as a catalyst.
Metals below hydrogen (Cu, Ag, Au, Pt), will not react with dilute acids. They cannot displace hydrogen from the non-metal anion.

REACTION WITH ACIDS

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Reaction with Concentrated Acids: HNO3 and H2SO4
Hydrogen gas is not evolved

when metals react with nitric acid (HNO3) because it is a strong oxidising agent and it oxidizes the H2 produced to water and is itself reduced to nitrogen dioxide:
1) With active metals:
Mg + HNO3(dilut) = Mg(NO3)2 + H2O + NH3 (NH4NO3)
Mg + HNO3(conc) = Mg(NO3)2 + 4H2O + 2N2O
2) With passive metals:
Cu + HNO3(dilut) = Cu(NO3)2 + H2O + NO
3Cu + 8HNO3(conc) = 3Cu(NO3)2 + 4H2O + 2NO2
Reaction with concentrated sulfuric acid:
Me + H2SO4 (conc) = MeSO4 + H2O + (H2S, S, SO2)
Fe and Al will not react with conc H2SO4 acid, they are passivated.

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Reaction with HNO3
Concentrated acid does not affect at the metals, they

are passivates

Cr, Fe, Al, Pt, Ta, Ir

Concentrated acid affect at the heavy metals, they are produced salt, water and NO2 gas

Heavy metals as
Cu, Ag, Au, Bi

Diluted acid affect at the heavy metals, they are produced salt, water and NO gas

Alkali and alkali earth metals and Sn, Fe

Concentrated acid affect at these metals, they are produced salt, water and N2O gas

Diluted acid affect at these metals, they are produced salt, water and NH3 gas (or salt NH4NO3)

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Explaining displacement reactions
The reactivity series can be used to predict if

a metal will react with a metal compound. If the metal is more reactive than the metal in the compound, it pushes out, or displaces, the less reactive metal from its compound.

If the metal is less reactive than the metal in the compound, it will not compete and so there is no reaction.

more reactive metal

less
reactive metal compound

more
reactive metal compound

less reactive metal



less reactive metal

more reactive metal compound

no reaction



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Reaction of metals with metal salt solutions and oxides
A displacement reaction

is one where a more reactive metal will displace a cation of less reactive metal from a compound (salt, oxide:

-2,37 V
active
metal

+0,34 V
passive
metal

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Displacement reaction
Zinc displaces copper from copper sulfate solution: Zn + CuSO4

ZnSO4 + Cu
Iron displaces copper from copper (II) sulfate:
Fe + CuSO4 FeSO4 + Cu

after 15 – 20 minutes

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The more reactive aluminium takes the oxygen from the less reactive

iron.
The reaction gets so hot that the iron melts! It is used to weld railway tracks.

Aluminium + Iron oxide => Aluminium oxide + Iron

In this reaction, aluminium reacts with iron oxide to make aluminium oxide and iron:

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Occurrence of metals :
Some metals like gold, silver, platinum etc

are found in the free state (nugget) in the earth’s crust because they are least reactive. Most metals are found as oxides, carbonates, sulfides, halides etc.
Minerals: are elements or compounds which occur naturally inside the earth’s crust.
Ore: is a mineral from which metals can be extracted profitably.
Gangue: is the impurities present in the ore like rock particles, sand particles, clay particles etc.

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Occurrence of metals in nature
High active metals
Medium active metals
Passive,

noble or precious metals

High active metals

are found in the salt types (chloride, sulfate, carbonate, silicate, phosphate):

are found in the oxides and sulfides types:

are found in the free state (nuggets)

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Extraction of metals from their ores :
The various processes involved in

the extraction of metals from their ores and refining them are known as metallurgy.
Metals are extracted from their ores in three main steps. They are :
Concentration of the ore (Enrichment of the ore).
Reducing the metal compound to the metal (by O2, H2, C, CO, Al and electrolysis)
Refining (Purification of the metal by electrolysis).

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Ways of Metal Extraction
Potassium K
Sodium Na
Calcium Ca
Magnesium Mg
Aluminium Al
Zinc Zn
Iron Fe
Tin Sn
Lead Pb
Copper Cu
Mercury Hg
Silver Ag
Gold Au
Platinum Pt
Extraction by electrolysis of molten Al2O3 dissolved in

cryolite
Extracted by electrolysis of molten chlorides
Extraction by reduction of oxides using carbon

Roasting ore by heating alone

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Steps involved in the extraction of metals from their ores
Metals

of Metals of Metals of
high reactivity medium reactivity low reactivity
Electrolysis of
molten ore Carbonate ore Sulfide ore Sulfide ore
Pure metal Calcination Roasting Roasting
Oxide of metal Metal
Reduction to metal Refining
Refining

Ore

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Using of Metals
Metal used in manufacturing are usually alloys, which are

composed of two or more elements, with at least one being metallic element.
Metals can be divided into two basic categories:
Ferrous
Non ferrous
Alloys are stronger and harder than pure metals and they also can with stand corrosion better. Pure metals are relatively a little softer (but they are still hard) and they have a low resistance to corrosion as they are affected by air and water easily. Hence alloys are used more often instead of pure metals. Nowadays, complex alloys have been made with specific desired properties. Usually, transition metals are used in the production of alloys.

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Ferrous Metals (black):
Ferrous metals are based on iron: the group includes

steel and cast iron. Pure iron has limited commercial use, but when alloyed with carbon. Iron has more uses and greater commercial value than any other metal.
Non ferrous (colored):
They include the other metallic elements and their alloys. They include metals and alloys of aluminum, copper, gold, silver and other metals.

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METALS ALLOYS
An alloy is a homogeneous mixture of a metal with

other metals or non metal:
Steel and cast iron – iron, carbon
Stainless steel – iron, carbon, cobalt, nickel
Brass – copper, zinc
Bronze – copper, tin
Solder – Lead, tin (used for welding electrical wires together)
If one of the metals in an alloy is mercury, it is called an amalgam.

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Metals

Содержание

Lecture Plan:Metal definitionCategories of various metalsThe structure of metal. Metallic bondProperties

OBJECTIVES:Understand the physical properties of metals.Explains the chemical properties of metals.Explain

A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a

Metallic Elements: Alkali metals (group IA): Li, Na, K, Rb, Cs,

Metallic Elements:4) Post-transition metals: Al, In, Ga, Sn, Tl, Pb, Bi,

The metallic bond causes many of the traits of metals, such

In a piece of metal, all the atoms lose their outer

REASONS:GIVE 3 REASONS WHY TUNGSTEN IS USED TO MAKE THE FILAMENT

PHYSICAL PROPERTIES OF METALSGood electrical and heat conductors.Malleable - can be beaten

Density of MetalsLight metals Heavy metalsMagnesium1,74 g/cm3Lead11,3 g/cm3Gold19,3 g/cm3Osmium22,5 g/cm3Lithium0,53 g/cm3Light

Melting point metalsRefractory metalsFusible metals

Metals have luster. This means they are shiny.Ductile metals can be

A chemical property of metal is its reaction with water and

These properties make metals most useful in daily life.

CHEMICAL PROPERTIES OF METALSUsually have 1-3 electrons in their outer shell.Lose

Reactivity series of metals The arranging of metals in the decreasing order

Use the reactivity series to predict if a reaction will take

Reaction with oxygen : Metals react with oxygen to form metal oxides:2Cu

Reaction of metals with water Those metals staying above hydrogen in electrochemical

K, Na, Li and Ca react violently with dilute H2SO4 and dilute

Reaction with Concentrated Acids: HNO3 and H2SO4Hydrogen gas is not evolved

Reaction with HNO3Concentrated acid does not affect at the metals, they

Explaining displacement reactions The reactivity series can be used to predict if

Reaction of metals with metal salt solutions and oxidesA displacement reaction

Displacement reaction Zinc displaces copper from copper sulfate solution: Zn + CuSO4