PowerPoint presentation of metals and nonmetals
name of the chapter: Metals and nonmetals
Content Provider: FIITJEE
Lecturer from FIITJEE
an intro that just known to us (recall):
- Metals are described as chemical elements that readily lose valence electrons to form positive ions (cations).
Examples: Aluminium, copper, iron, tin, gold. - Around 90 of the total 118 elements are metals.
To know more about Metals, visit
Physical Properties
Physical Properties of Nonmetals
- Occur as solids, liquids, and gases at room temperature
- Brittle
- Non-malleable
- Non-ductile
- Non-sonorous
- Bad conductors of heat and electricity
Exceptions in Physical Properties
- Alkali metals (Na, K, Li) can be cut using a knife.
- Mercury is a liquid metal.
- Lead and mercury are poor conductors of heat.
- Mercury expands significantly for the slightest change in temperature.
- Gallium and cesium have a very low melting point
- Iodine is non-metal but it has luster.
- Graphite conducts electricity.
- Diamond conducts heat and has a very high melting point.
Physical Properties of Metals
● Hard and have a high tensile strength
● Solids at room temperature, except mercury, which is liquid at room temperature.
● Sonorous
● Good conductors of heat and electricity
● Malleable, i.e., can be beaten into thin sheets
● Ductile, i.e., can be drawn into thin wires
● High melting and boiling points (except Cesium (Cs) and Gallium (Ga))
● Dense, (except alkali metals). Osmium – highest density and lithium – least density
● Lustrous
● Silver-grey in color, (except gold and copper)
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INTRODUCTION
Classification of
elements based on their physical and chemical
properties :
Ø Metals
( eg: gold,silver,copper,potassium,sodium,aluminium etc.,)
Ø Non
metals (eg:carbon,chlorine,phosphorus,oxygen,bromine,etc..,)
Ø Metalloids
- Exhibit properties of both metals and
non metals (eg: silicon, germanium,boron,arsenic,antimony
etc.,)
Total number of elements = 118 Naturally occuring = 92
Physical
Properties
Metals:
·
Generally solids at room temp,
Exception: Gallium
and Mercury
are liquids
* They are lustrous (shine)
* Metals are malleable (beaten into sheets) GOLD is the
most malleable metal
* Metals are ductile( drawn into wires
* Metals are hard
Exception: Sodium, Potassium, Caesium, Lead
·
High M.P and B.P
·
Exception: Sodium, Potassium, Lithium
·
Metals are good conductors of heat and electricity
·
Silver is the best conductor of heat and electricity followed by Cu, Au, Al
·
Exception: Lead and Mercury are
·
poor conductors of heat
Non-Metals:
* Exist as solids, liquids, and gases at room temperature
* Bromine is a liquid nonmetal
* Non - lustrous
Exception: Iodine, Diamond
Graphite
* They are non-malleable
* non-ductile
* Nonmetals are generally soft and some are brittle (they break on heating)
Exception: Diamond is the hardest substance
·
Low M.P and B.P
Exception: Carbon
Bad conductors of heat and electricity
Exception: Graphite is a good conductor of electricity
AMPHOTERIC OXIDES
•
Such
metal oxides which react with both acids as well
as bases to produce salts and water are
known as amphoteric oxides.
•
Aluminum oxide reacts in the following manner
with acids and bases –
(BASE) Al2O3 + 6HCl → 2AlCl3 +
3H2O
(ACID)Al2O3 + 2NaOH → 2NaAlO2 (Sodium aluminate)+ H2O
Zinc and aluminum oxides are examples of amphoteric oxides
REACTION WITH OXYGEN ( NON-METALS)
•
When non-metals react with the oxygen they form their
respective oxides and by adding a small amount
of water, the solution becomes acidic.
•
Eg: S +O2 → SO2 ; SO2 + H2O → H2SO3
REACTION WITH WATER (METALS)
•
Metal + Water → Metal oxide + Hydrogen
•
Metal oxide + Water → Metal hydroxide
•
Metals like potassium
and sodium react violently with cold water.
In the case of sodium and potassium, the reaction
is so violent and exothermic that the evolved hydrogen immediately catches fire.
•
2K(s) +
2H2O(l) → 2KOH(aq) + H2(g) + heat energy
•
2Na(s) + 2H 2O(l) → 2NaOH(aq) + H2(g)
+ heat energy
•
The reaction of calcium with water is less violent.
The heat evolved is not sufficient for
the hydrogen to catch fire.
Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)
•
Magnesium does
not react with cold water.
It reacts vigorously with
hot water to form magnesium hydroxide and hydrogen.
•
Metals like aluminum,
iron, and zinc do not react either with cold
or hot water. But they react with steam to form metal oxide and hydrogen. 2Al(s) + 3H2O(g) → Al2O3(s) + 3H2(g)
•
3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g)
•
Metals such as lead, copper, silver, and gold do
not react with water at all.
REACTION WITH WATER (NON-METALS)
•
Nonmetals do not react with water.
•
Some non-metals like phosphorus is kept in water,
so that its contact from the air can be avoided.
REACTION WITH ACIDS (METALS)
Metal + Dilute acid → Salt + Hydrogen
Eg: 2Al + 6HCL→2AlCl3 +3H2
Fe + HCl → FeCl2 + H2
•
Copper does not react with dil.HCl but reacts
with conc. sulphuric and nitric acid.
•
Hydrogen gas is not evolved when a metal
reacts with nitric acid because HNO3
is a strong oxidizing agent.
•
It oxidizes the H2 produced to water
and itself gets reduced to any of the nitrogen
oxides (N2O, NO, NO2).
•
But
magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve Hydrogen gas.
REACTION WITH ACIDS (NON-METALS)
•
Nonmetals do not react with acids, although sulfur
reacts with hot concentrated nitric acid.
S+ 4HNO3→SO2 + 4NO2 +2H2O
•
METAL REPLACES METAL: Reactive metals can displace
less reactive metals from their compounds
in solution or molten form.
Metal A + Salt solution of B → Salt solution of A + Metal
B
Fe+CuSO4→ FeSO4+ Cu Mg+CuSO4 →MgSO4+Cu
Nobel Metals
Metals that have very less tendency to react, that resisted chemical action, do not corrode, and can be found in a free
state in nature are known as noble
metals. eg: gold,silver,platinum etc.,
Gold dissolves in aqua
Regia (A mixture of conc.HNO3 and conc
HCL in the ratio 1:3 by volume)
USES OF METALS
• Iron
is the most commonly used metal, for the construction of
ships,buildings, automobiles and railway bridges, etc
is used for making jewelry, wires, and coins and in dentistry
• Silver
is used for making wires, utensils, statues, alloys, good reflecting
property of silver is also used in making mirrors
• Tin
is used for tinning food cans and alloys
• Lead
is used for making batteries and alloys
• Zinc
is used in the prevention of rusting, making alloys, and in dry cells
• Mercury
is used in making amalgams (an alloy of mercury with another metal,
especially one used for dental fillings) and in thermometers
• Cu
and Al is used in making wires, Al in food packing and in airplane
parts
is used as the filament in incandescent light bulbs because it
has the
highest melting point
Corrosion
• Corrosion
is an oxidation reaction with atmospheric oxygen in the presence of water on the surface of a metal.
• During corrosion, metals get converted
to oxides, hydroxides, sulfides, etc.
• The
corrosion of iron is called rusting
Fe + O2 → Fe2O3 (Rust which is brown in color) + H2O
• Corrosion of copper: Copper reacts with moisture,
carbon dioxide and oxygen in the air and slowly
loses its shiny brown surface and gains a
green coat. This green substance is copper carbonate.
Cu+ CO2+ H2O+ O2 → CuCO3.Cu(OH)2
• Tarnishing of silver: Silver reacts with
sulfur (generally H2S) in the atmosphere and the information of silver sulfide which is black in color.
Ag+H2S→ Ag2S
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