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Chapter 1:Chemical Reaction And Equations

Chapter 2:Acids, Bases and Salts

Chapter 3:Metals and Non-metals

Chapter 4:Carbon and Its Compounds

Chapter 5: Periodic Classification of Elements

Chapter 6: Life Processes

Chapter 10: Light Reflection and Refraction

Chapter 11:Human Eye and Colourful World

Chapter 12:Electricity

Chapter 13:Magnetic Effects of Electric Current

Chapter 14:Sources of Energy

Chapter 15:Our Environment

Chapter 16:Sustainable Management of Natural Resources

Metals and Non-metals class 10 notes chapter 3

All the element can be divided into two group on the basis of their property
i)Metal
ii)Non Metal

Metals:
i) Metal are the element that conduct heat and electricity ,ductile and malleable .The samples of following metals – iron, copper, aluminium, magnesium, sodium, lead, zinc and any other metal that is easily available.
ii)Metals are the elements which form positive ions by losing electrons. Thus, metals are known as Electropositive Elements.

PHYSICAL PROPERTIES METALS:
Hardness: Most of the metals are hard, except alkali metals, such as sodium, potassium, lithium, etc. are very soft metals. These can be cut by using a knife.
Strength: Most of the metals are strong and have high tensile strength. Because of this, big structures are made using metals, such as copper (Cu) and iron (Fe). (Except Sodium (Na) and potassium (K) which are soft metals).
. lustre Metal have a shining surface. This property is called metallic lustre
State: Metals are solid at room temperature except for mercury (Hg).
Sonorous Metals produce ringing sound, so, metals are called Sonorous. Sound of metals is also known as Metallic sound. This is the cause that metal wires are used in making musical instruments.
Conduction: Metals are a good conductor of heat and electricity..
Malleability: Metals are malleable. This means metals can be beaten into a thin sheet. .
Ductility: Metals are ductile. This means metals can be drawn into thin wire. Because of this property, a wire is made of metals.
Melting and Boiling Point: Metals have generally high melting and boiling points. (Except sodium and potassium metals which have low melting and boiling point.)
Density: Most of the metals have a high density.
Colour: Most of the metals are grey in colour. except gold and copper

Non-Metals:
i) Non metal are elements that do not conduct electricity and heat and they are neither ductility
ii) Non metals are the elements which form negetive ions by gaining electrons. Thus, metals are known as Electronegetive Elements.

PHYSICAL PROPERTIES NON-METALS:
i) Non metals do not show the properties of melleabilty and ductile
ii)Non metal do not conduct heat and electricity
iii)Non metal are generally soft except diamond
iv)Non metal do not so lustrous properties but Iodine is a non-metal but it is lustrous
v) Non metal have very low melting point and boiling point except diamond

CHEMICAL PROPERTIES OF METALS:
Reaction of metals with air(oxygen):
Almost all metals combine with oxygen to form metal oxides.
Metal + Oxygen → Metal oxide


Note:metal oxides are basic in nature.
Amphoteric oxides The metal oxide which show both acidic as well as basic behaviour are known as amphoteric oxides



Alkalis Most metal which dissolve in water to form alkalis



-> magnesium, aluminium, zinc, lead react slowly with air and form a protective layer that prevents corrosion.
Question: Why pottasium and sodium metal kept in kerosene oil ?
Ans: potassium and sodium react so vigorously that they catch fire if kept in the open. So they are kept immersed in kerosene oil

Reaction of metals with water:
when metals reacting with water to form metal hydroxide and hydrogen gas
Metal + Water Metal hydroxide + Hydrogen
Metal + Steam Metal oxide + Hydrogen

Metals like potassium and sodium react violently with cold water.
2K(s) + 2H2O(l) 2KOH(aq) + H2(g) + heat energy
2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g) + heat energy
sodium and potassium, the reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.

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 with hot water to form magnesium hydroxide and hydrogen
Mg(s) + 2H2O(l) Mg(OH)2(aq) + H2(g)
It also starts floating due to the bubbles of hydrogen gas sticking to its surface.

Metals like aluminium, iron and zinc do not react either with cold or hot water. But they react with steam to form the 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

When Metals react with Acids:
Metal + Dilute acid → Salt + Hydrogen

Q: when metal react with dilute nitric acid then gas is not form.Why?:

Ans:Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO3 is a strong oxidising agent. It oxidises the H2 produced to water

magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve H2 gas.

Metals react with Solutions of other Metal:
Salts Metal A + Salt solution of B → Salt solution of A + Metal B

The Reactivity Series:
The reactivity series is a list of metals arranged in the order of their decreasing activities

How Do Metals and Non-metals React:
When metal react with non metal they form ionic compounds
Metals lose valence electron(s) and form cations.
Non-metals gain those electrons in their valence shell and form anions.
The cation and the anion are attracted to each other by strong electrostatic force, thus forming an ionic bond.
For example: In Sodium Chloride the ionic bond is formed by opposite charged Sodium and chloride ions. sodium atom has one electron in its outermost shell. If it loses the electron from its M shell then its L shell now becomes the outermost shell and that has a stable octet. The nucleus of this atom still has 11 protons but the number of electrons has become 10, so there is a net positive charge giving us a sodium cation Na+. On the other hand chlorine has seven electrons in its outermost shell and it requires one more electron to complete its octet. If sodium and chlorine were to react, the electron lost by sodium could be taken up by chlorine. After gaining an electron, the chlorine atom gets a unit negative charge, because its nucleus has 17 protons and there are 18 electrons in its K, L and M shells. This gives us a chloride anion C1

ii)

Ionic Bond:
The transfer of electron from one atom to another to formed chemical bond is known as ionic bond

Properties of Ionic Compounds:

  • Physical nature:: Ionic compounds are solids and are somewhat hard because of the strong force of attraction between the positive and negative ions. These compounds are generally brittle and break into pieces when pressure is applied
  • Melting and Boiling points: : Ionic compounds have high melting and boiling points . This is because a considerable amount of energy is required to break the strong inter-ionic attraction
  • Solubility: Electrovalent compounds are generally soluble in water and insoluble in solvents such as kerosene, petrol, etc.
  • Conduction of Electricity: ionic compounds conduct electricity in the molten state. This is possible in the molten state since the elecrostatic forces of attraction between the oppositely charged ions are overcome due to the heat. Thus, the ions move freely and conduct electricity

Covelent Bond:
The sharing of electron between two atom to formed chemical bond are known as covelent bond

Properties of Covelent Bond:

i) Covelent compound are usually liquids or gases Some of them are solid (diamond and Silica etc)

ii)Covelent compound have very low melting and boiling points

iii)Covelent compound are insoluble in water but the are soluble in organic solvent

iv)Covelent compound do not conduct electricity

OCCURRENCE OF METALS:
The earth’s crust is the major source of metals. Seawater also contains some soluble salts such as sodium chloride, magnesium chloride, etc.

Minerals:
The elements or compounds, which occur naturally in the earth’s crust, are known as minerals

Ores:
Msinerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores

Extraction of Metals:
The obtain a metal from oresis known as extracted of metal

Matallurgy:
The process of extracting pure metal form their ores is called metallurgy

Different techniques are to be used for obtaining the metals falling in each category


Metal
K
Na
Ca
Mg
Al




Zn
Fe
Pb
Cu




Au
Hg
(i) Metals of low reactivity::
The metals ( gold, silver, platinum and copper) at the bottom of the activity series are the least reactive. They are often found in a free state
ii)Metals of medium reactivity:
The metals in the middle of the activity series (Zn, Fe, Pb, etc.) are moderately reactive. They are found in the earth’s crust mainly as oxides, sulphides or carbonates.
(iii) Metals of high reactivity:
The metals at the top of the activity series (K, Na, Ca, Mg and Al) are so reactive that they are never found in nature as free elements

Enrichment of Ores:

Gangue:
The mineral contain large amounts of impurities such as soil, sand, etc., called gangue.

Extracting Metals Low in the Activity Series:
The oxides of these metals can be reduced to metals by heating alone.
For example : cinnabar (HgS) is an ore of mercury. When it is heated in air, it is first converted into mercuric oxide (HgO). Mercuric oxide is then reduced to mercury on further heating.
ii) copper which is found as Cu2S in nature can be obtained from its ore by just heating in air.

Extracting Metals in the Middle of the Activity Series:


Roasting:
The sulphide ores are converted into oxides by heating strongly in the presence of excess air. This process is known as roasting

Calcination:
The carbonate ores are changed into oxides by heating strongly in limited air. This process is known as calcination.

Uses of displacement reaction:
i)Extraction of metals
ii)Manufacturing of steel
iii)Thermite reaction: the reaction of iron(III) oxide (Fe2O3) with aluminium is used to join railway tracks or cracked machine parts. This reaction is known as the thermit reaction.
Al(s)+Fe2O3(s) Al2O3+Fe(molten)

Extracting Metals towards the Top of the Activity Series:
These metals are obtained by electrolytic reduction

At the cathode (reduction):
Na+(molten) +e- Na(s)
Metal is deposited.
At the anode (oxidation):
2Cl-(molten) Cl2(g) + 2e-
Chlorine gas is liberated.

Refining of Metals:
The process of purifying impure metal is called refining of metal

Electrolytic Refining:

Metals like copper, zinc, nickel, silver, tin, gold etc., are refined electrolytically.
Anode: impure or crude metal
Cathode: a thin strip of pure metal
Electrolyte: aqueous solution of metal salt
From anode (oxidation): metal ions are released into the solution
At cathode (reduction): the equivalent amount of metal from solution is deposited Impurities deposit at the bottom of the anode

CORROSION
The eating up of metal by action of air moisture or a chemical on their surface are called corrosion

Alloy
A homogeneous mixture of two or more metal or metal and non-metal are called alloy
Examples of alloys –
Brass: copper and zinc
Bronze: copper and tin
Solder: lead and tin

Amalgam
Special class of alloys in which there is mixture of metal and mercury

Rusting of Iron
Rust is an iron oxide, a usually reddish brown oxide formed by the reaction of iron and oxygen in the presence of water or air moisture.

4Fe(s)+3O2(from air)+xH2O(moisture)→2Fe2O3. xH2O(rust)

Prevention of Corrosion:
i)The rusting of iron can be prevented by painting, oiling, greasing,
ii)Galvanisation is a method of protecting steel and iron from rusting by coating them with a thin layer of zinc
iii)Rusting of iorn can be prevented by alloying it to make stainless steal
iv)Rusting of iorn can be prevented by tin-plating