INTRODUCTION

In this chapter we will learn about metals and non-metals in very details. We know that on the basis of the physical and chemical properties, we can classify elements into metals and non-metals. 

Iron bars : Metal

Sulphur : Non-metal

Metal and non-metals are present all around us. For example, iron, aluminium, silver, gold, etc., are some examples of metal and coal, sulphur, phosphorus, chlorine, etc., are some examples of non-metals. Metals are hard and lustrous, whereas non-metals are brittle and dull in appearance.

METALS

You know that elements like iron, aluminium, silver, gold are metals. Let us now see the physical properties of metal :- 

• State: Metals are generally solid at room temperature except mercury which is liquid at room temperature. Metals have high melting and boiling points.
  Note: Iron has a melting point of 1535 degree C and copper has a melting point of 1083 degree C.
• Hardness: Metals are generally hard but metals like sodium and potassium are soft and can be cut through a knife. Also metals like gold and aluminium are not very hard.
• Lustre: When metals are freshly cut, they have a brilliant shine over the cut surface. This metallic surface is called lustre.
• Density: Metals generally have higher density. Lithium, sodium and potassium are exceptions here as their density is less than 1 g/cm³ , also these metals can float on water.
  Note: Iron has a density of 7.8 g/cm³. Density lesser than 1 g/cm³ can float on water like ice.
• Melting and boiling points: Metals have high melting and boiling point. Mercury and gallium metals are exception as they have low melting and boiling point.
• Sonorous: When metals are struck with some hard material, they produce a ringing sound. This characteristic of metal is called Sonorous
• Malleability: The property of metals, due to which they can be beaten into thin sheets, is called malleability.
• Ductility: The property due to which a substance can be drawn into thin wires is called ductility.
• Conductivity: Metals are generally good conductors of heat and electricity. Silver is the best conductor. Copper and aluminium are also good conductors of heat. But metals like bismuth and tungsten are bad/poor conductors.

Now, let us do two assignments and one quiz for concept clearance (max 15 mins)

• Click here to do assignment 1
• Click here to do assignment 2
• Click here for QUIZ

RANKING METALS

Ranking metals is very important because it helps us to know which metals are Most reactive and least reactive metals in a series form. For ranking metals we did some experiments like reacting metals with oxygen, water and acid. Here we will also know the nature of metal oxides in between this experiments.

METAL REACTION WITH OXYGEN

Let us take do the experiment following experiment of metals with oxygen.

Experiment 1: Magnesium with oxygen

Let us take a shiny piece of magnesium ribbon and burn it. At the end we will left with a powdery substance as residue which is magnesium oxide. 
When magnesium is burnt it combines with oxygen molecules to form magnesium oxide with is white in color. The chemical equation is

2Mg + O₂ ------> 2MgO

MAGNESIUM IS BEING BURNT

MAGNESIUM OXIDE

EXPERIMENT 1 VIDEO

Experiment 2: Copper with oxygen

Let us take some shiny copper ribbon and heat for sometime. You will notice that the colour changes to black. Here also copper atoms are combining with oxygen molecules in the airand forming copper oxide which is black. The chemical equation is

2Cu + O₂ ------> 2CuO

COPPER IS BEING BURNED

COPPER AFTER BEING BURNED CHANGES IT'S COLOR TO BLACK. THIS IS COPPER OXIDE.

EXPERIMENT 2 VIDEO

Conclusion of both experiments

So you saw that when metals are burnt or heated in air or oxygen, the metals are converted into metal oxides in almost for all the metals. Like magnesium and copper are converted into there oxides which are magnesium oxide and copper oxide respectively.

Metal + Oxygen ------> Metal Oxide

You have to also remember that their are exceptions that don't give out metal oxides. Like gold and silver, these two metals with never combine with oxygen to form oxides.

Note: Chemical symbol for gold is 'Au' and for silver is 'Ag'.

So now let us rank our metals according to how strongly and weakly the metals react with oxygen.

RANKING OF METALS ACCORDING TO HOW THEY REACT WITH OXYGEN

Ranking of metals can be done in different ways. First let us react metals with oxygen to rank metals to see how strong and weak the metal react.

Now let us take sodium. If we keep sodium in the open air for a long time it will catch fire without heating it. This is a vigorous reaction as it reacts with oxygen automatically and catches fire. So we never keep sodium in open air, we store it by dipping it in kerosene so that it never comes contact with air or water. Same with potassium, it's reaction with oxygen is also vigorous. Therefore we keep 'Na' and 'K' in rank 1

RANK 1: Na, K

FIRST RANK - Na and K

So now let us take magnesium. We have already seen that when magnesium is burnt, It burns with a dazzling white flame. It is also reactive but in comparison with sodium and potassium it can only come in the second rank.

RANK 2: Mg

SECOND RANK - Mg

So now metals like aluminium, zinc, copper and iron, all react with oxygen in similar fashion to form their individual oxides. Since these metals don't react vigorously like magnesium or sodium. So aluminium, zinc, copper and iron are grouped in third rank. Here we will notice that aluminium, zinc and iron will burn and react with oxygen to form their oxides but when copper reacts is burnt, it will get hot and then it will react with oxygen to form copper oxide which is black in color.

Note: The symbols of aluminium, zinc, iron and copper are 'Al', 'Zn', 'Fe' and 'Cu' respectively.

RANK 3: Al, Zn, Fe, Cu

THIRD RANK - Al, Zn, Fe, Cu

Now the last rank which is the fourth rank includes gold and silver. These metals when you will heat up, these metals will not react with oxygen. So these metals are also given a name, which is 'noble metals' or 'peaceful metals', these are the least reactive in our list.

Note: The symbols of gold and silver are 'Au' and 'Ag' respectively.

RANK 4: Au and Ag

FOURTH RANK - Au and Ag

So since we have completed our ranking of metals according to how they react with oxygen. Lets just see a total over view through the under given table from the most reactive to the leas reactive.

There are some metals which on kept on normal room temperature will react with oxygen, without heating and form oxides. Metals like aluminium when kept in open air, it will form oxide by reacting with oxygen and the outermost layer of the metal will form a precipitate and prevents oxygen from entering inside aluminium. This means that the outermost layer sacrifice itself to protect the rest of the metal. This can be also be seen in metals like sodium, magnesium, zinc, etc. These metals will form oxides which will form a layer outside the metal to avoid oxygen from entering the rest of the metal.

Still this list is not detailed. For more detailing the list we will further react this metals with water and acid.

NATURE OF METAL OXIDES

So before going further about ranking metals, let us learn about metal oxides. So first let us know that metal oxides are acidic or basic in nature. So the answer is, metal oxides are basic in nature. So some metal oxides are used as antacids to neutralize the excess acid in our body.

So now let us see why metal oxides are basic in nature, but first we will recall what we have learned -

Acid + Base ----> Salt + Water ---(1)

So acid and base when add, neutralize each other's reaction and form salt and water. So if 'Acid + ? ---> Salt + Water' is given and it is told that some random chemical is mixing with an acid to form salt and water as their products, then he chemical must be basic in nature because we know that which acid is added to base then the products will be salt and water. Therefore the answer will be 'Acid + Base ----> Salt + Water'.

Now let us mix metal oxide with acid. For example -

HCl + Na₂O -------> NaCl + H₂O

Here 'Na₂O' is sodium oxide which is a metal oxide and it reacts with acid (which we have taken 'HCl') and form 'NaCl' which is a salt and 'H₂O' which is water. Before concluding let us balance this equation. So the balanced equation is -

2HCl + Na₂O -------> 2NaCl + H₂O

Now from (1), we can conclude that 'Na₂O' is base, but we know that 'Na₂O' is a metal oxide. Therefore, metal oxides are basic in nature.

One more example can be seen which is -

HCl + CaO -----> CaCl₂ + H₂O

Here also 'CaO' is calcium oxide which is a metal oxide. We have also added an acid which is 'HCl'. Both of them react to form 'CaCl₂' and 'H₂O'. Here 'CaCl₂' is a salt and 'H₂O' is water. First lets see the balanced equation -

2HCl + CaO -----> CaCl₂ + H₂O

Here also we can get say that metal oxides are basic in nature like the previous example. We learnt from both the examples that metal oxides are generally basic in nature. But their are some exceptions. There are some metal oxides which not only acts as a base but also can act as an acid to form salt and water. So now let us see some examples of it -

Example 1: (i) First let us react that metal oxide as a base with an acid -

HCl + Al₂O₃ ------> AlCl₃ + H₂O

Balanced equation of the above chemical equation is -

6HCl + Al₂O₃ ------> 2AlCl₃ + 3H₂O

Here 'Al₂O₃' is a metal oxide which acts as a base and reacts with acid which is 'HCl' to form 'AlCl₃' with is a salt and 'H₂O' which is water.

(ii) Now let us react that metal oxide as an acid with a base -

Al₂O₃ + NaOH ------> NaAlO₂ + H₂O

Balanced equation of the above chemical equation is -

Al₂O₃ + 2NaOH ------> 2NaAlO₂ + H₂O

Here 'Al₂O₃' is a metal oxide which acts as an acid and reacts with a base 'NaOH' to form 'NaAlO₂' which is a salt and 'H₂O' which is a water.

Therefore we can say that 'Al₂O₃' can act as a base and as well as an acid. So 'Al₂O₃' is an exception.

Example 2: Another exception is 'Zinc oxide' which is 'ZnO'.
(i) First let us react this metal oxide as a base with an acid -

HCl + ZnO -------> ZnCl₂ + H₂O

Balanced equation is -

2HCl + ZnO -------> ZnCl₂ + H₂O

Here 'ZnO' is a metal oxide which acts as a base and reacts with an acid 'HCl' to form 'ZnCl₂' which is a salt and 'H₂O' which is a water.

(ii) Now let us react this metal oxide as an acid with a base -

ZnO + NaOH ------> Na₂ZnO₂ + H₂O

Here 'ZnO' is a metal oxide which acts as an acid and reacts with a base 'NaOH' to form 'Na₂ZnO₂' which is a salt and 'H₂O' which is a water.

Note - 
(i) 'HCl' is 'Hydrochloric acid'.
(ii) 'Na₂O' is 'Sodium oxide'.
(iii) 'NaCl' is 'Sodium chloride'.
(iv) 'Al₂O₃' is 'Aluminium oxide'.
(v) 'AlCl₃' is 'Aluminium chloride'.
(vi) 'NaOH' is 'Sodium hydroxide'.
(vii) 'NaAlO₂' is 'Pure sodium aluminate'.
(viii) 'H₂O' is 'water'.
(ix) 'ZnO' is 'Zinc oxide'.
(x) 'ZnCl₂' is 'Zinc chloride'.
(xi) 'Na₂ZnO₂' is 'Sodium zincate'.

Now we can say the following things -

• Metal oxides are generally basic in nature.
• Some metal oxides are amphoteric. Amphoteric means that metal oxides are both acidic and basic in nature. Example - Al₂O₃, ZnO, etc.

Now let us see some more about amphoteric.

AMPHOTERIC

So now we know that 'NaO' is a metal oxide which will mix with acid to form salt and water. Also 'NaOH' is a base when on mixing with an acid forms salt and water. Now you will think that 'what is the relation between 'NaO' and 'NaOH' ?'. So the relation is given below -

NaO + H₂O ------> NaOH

So, the key point is that their are some metal oxides which are soluble in water and insoluble in water. Like you take add a teaspoon of salt in water, then it will mix without any residue and will form salt solution. Similarly metal oxides like sodium oxide (NaO), potassium oxide (K₂O), calcium oxide (CaO), etc., will dissolve in water and will form hydroxides. Whereas metal oxides like magnesium oxide (MgO), aluminium oxide (Al₂O₃), etc., does not dissolve in water but 'MgO' dissolves with water in a very little extent which is almost negligible. Now metal oxides such as NaO will dissolve in water to form 'NaOH' which is metal hydroxide.

So from this topic of 'Nature of metal oxides and Amphoteric', some questions comes in our mind -

1. Metal oxides generally are _______ in nature.
2. Some metal oxides are ________ i.e., both acidic and basic.
3. Give two example of amphoteric.
4. Write one example each of soluble and insoluble metal oxides in water.

After you have revised let's move to the next part which is 'Metals reacting with water'

METAL REACTION WITH WATER

Now lets rank metal according to how vigorously the metals react with water from the most reactive to the less reactive metal. The table that we had made during the topic of 'Metal reaction with oxygen', we will format that and will create a new table. The table that we made previous is -

So in rank three we could not divide the metals into further ranks. So with the help of this water we can classify metals into more ranks.

Generally when metals react with water, the metal displaces hydrogen and forms metal oxide and hydrogen gas.

Metal + H₂O ------> Metal oxide + H₂ (↑)

Remember that some metal oxides react with water to form metal hydroxide. So that mean that if this metal oxide can react with water then it will directly form metal hydroxide.

Metal oxide + H₂O -------> Metal hydroxide

So that means that the product of metal and water may be metal oxide in which hydrogen is evolving or it may be metal hydroxide in which hydrogen is evolved. So for example when a small amount of sodium is reacted with water, it will form sodium oxide and hydrogen gas. But since sodium oxide on reacting becomes sodium hydroxide and with it a lot of heat will be too given out. Therefore the result stands as -

Na + H₂O -----> NaOH + H₂ (↑) + Heat

So let's see the experiment in a video -

So we will see that when we put sodium in the water, it cannot stay still in one place and it dances over the water surface. This is because when the sodium is added hydrogen gas is produced, this hydrogen gas pushes the sodium in different directions and it looks like it is dancing. The heat that is produced is so much that it can burn the hydrogen gas and eventually the sodium disappear in the water because it reacts very violently with water and turns into sodium hydroxide. This can be tested using pH paper because since sodium hydroxide is a base so it will turn red litmus into blue and blue litmus will not change it's color as shown in the picture below -

Note: Sodium is so reactive that it even reacts with cold water.

Similarly potassium will also react with water like sodium and will produce heat in large amount. So now we keep rank sodium and potassium at rank 1 in the reactive series.

Now let us take calcium. When calcium is reacted with water, it forms calcium hydroxide and hydrogen which is evolved. This also releases heat, but as compared to sodium, calcium releases less heat. This heat is not sufficient to burn the hydrogen gas. The chemical formula is -

Ca + H₂O (cold) -----> Ca(OH)₂ + H₂ (↑) + Heat

The hydrogen gas will not burn but instead will be bubbling out of the water solution and stick to calcium metal and it will make it float in the water. So we rank calcium as rank 2. You can check the experiment by seeing the under given video -

Now let us take magnesium. When magnesium is added to cold water, it doesn't react so we add hot water instead of cold water to react. From this we can conclude that magnesium is not more reactive than calcium. Therefore we can rank calcium in rank 3. The chemical formula is -

Mg + H₂O ------> Mg(OH)₂ + H₂ (↑)

Now we have aluminum which on reacting with water gives out aluminium oxide and water. We have to remember that aluminium oxide is not soluble in water and so it will not form hydroxide. Here aluminium doesn't react with water but with steam which is in gaseous state. The chemical formula is -

Al + H₂O -------->Al₂O₃ + H₂ (↑)

Iron and zinc also react in this similar way. We can notice that since aluminium doesn't react with water but with steam, then it is less reactive than magnesium. Therefore we can place aluminium, iron and zinc in rank 4.

Metals like copper, lead, gold and silver doesn't react with water or steam. Therefore these metals can be placed in rank 5.

Mark down the table.

First row is serial number. Second is the name of the metals. Third row is about with which form of water these metals react with and fourth row is what happens to the hydrogen when evolved.

So the updated table of reactive series is -

This list is still not fully detailed. For detailing we have to react metals with acid.

ASSIGNMENTS

There are three assignment based on how much you have learnt after completing the last assignment that was given.

• Click here for assignment no. 3
• Click here for assignment no. 4
• Click here for assignment no. 5

METAL REACTION WITH ACID

Here we will continue ranking metals by reacting metals with dilute acid and after this we can fully complete our ranking of metals. So when metals react with dilute acid, the products are - Hydrogen gas which is released and metal salt is formed. The formula is -

Metal + Dil. acid -----> H₂(↑) + Metal salt

For example when zinc reacts with dilute hydrochloric acid then hydrogen is evolved and form zinc chloride which is a metal salt. The chemical equation for this is -

Zn + Dil. HCl -------> H₂(↑) + ZnCl₂

Now we can also observe that when zinc is added to dilute hydrochloric acid then we can notice that with the reaction heat is evolved. Now in the equation we will add heat on the product side with showing the balanced equation -

Zn + 2HCl -------> H₂(↑) + ZnCl₂ + Δ (heat)

Note - (i)  This symbol 'Δ' is a symbol of 'heat' in chemistry.
(ii) Dil. was written in previous equation for explaining that the acid is dilute acid.

From the heat evolved we can conclude that how much reactive the metal is. Also tin the experiment when zinc is added to 'HCl', bubbles form, this bubbles are hydrogen. Now let us see the experiment in a video.

Experiment video -

Now let us now take magnesium metal. When magnesium is added to dilute HCl then the bubbles that are formed are very vigorous and much more amount of heat can be observed in case of magnesium than zinc. The chemical reaction is -

Mg + 2HCl -------> H₂(↑) + MgCl₂ + Δ

So we can conclude that magnesium is more reactive than zinc.

Magnesium experiment -

So if we do all metals then we can conclude that maximum bubbling happens in magnesium then aluminium the zinc and then iron. Least bubbling happens with iron. Now if we take copper, we will notice that no bubbling happens with copper.

Mg > Al > Zn > Fe > Cu

So with the new information, let us update our ranking of metals -

See that we have done sorting the metals in different ranks but see that Cu and Pb are not sorted, for that we have to do some more chemical reactions which we will do later.

Note - (i) Don't react sodium and potassium with acid because it is very much reactive and even cause harm to you.

(ii) We know that when metals react with acid, they give out hydrogen gas, but this is not true for nitric acid and it is a very good oxidizing agent, so when hydrogen when produced gets oxidized and therefore we get water instead of hydrogen.

(iii) Only magnesium and manganese are the two metals which react with a very dilute form of nitric acid to form hydrogen.

REACTIVITY SERIES

Now let us say you have calcium chloride and you want the calcium metal out from this compound. For removing calcium you must react the compound with more reactive metal than calcium. Let us say iron. Now you will say that how to remember this, for that you need to memories the chart given below -

For making the reactive list we will react metal with salts of other metals. Let us take salt of copper that is copper sulphate. Now to get copper out of the metal salt we need to react this with a more reactive metal than copper. According to the list we can take iron because iron is more reactive than copper. So now iron will replace copper and the products will be copper and iron sulphate.

Now if we do the reverse like reacting copper with iron sulphate then their will be no products. Therefore we can conclude that copper is less reactive than iron. Similarly take another example for clarification, like zinc reacting with copper sulphate. Then zinc will replace copper and the products will be copper and zinc sulphate but when copper is reacted with zinc sulphate then their is not product because only high reactve metals can only displace a low reactive metal but a low reactive metal cannot displace a high reactive metal.

So now for knowing which metal can displace which metal, we have to memorize the chart. For memorizing we can follow the following chart -

In your book you will see that in this chart their are some extra metal and carbon which is a non-metal. If you can memorize this chart, this will be helpful for future chemistry chapters.

For reference, you can watch the video of reactivity series here -

ASSIGNMENTS

There are three assignment based on how much you have learnt after completing the last assignment that was given.

• Click here for assignment 6
• Click here for assignment 7

IONIC BONDS : REACTING METAL WITH NON METAL

So when sodium reacts with chlorine we get sodium chloride or NaCl, but how does this happen at an atomic level ?, So in this topic we will get the answer of this question and also react metal with non-metal and also what are ionic bonds and how are they formed?, before starting we must know a few things. First we need to remember the electronic configuration and noble gases

Noble gases are also called inert gases which don't take part in any chemical reaction. So may be we can understand form their that why the elements want to react.

Let us take neon for example. Neon is a noble gas. It has 10 protons and since this is a neutral atom of neo so their will be 10 electrons too. Now the electron which do not go at any place to revolve, it moves around the element in circular paths or fixed regions called shells. So there are four shells named 'K', 'L', 'M', 'N'.

So now let us see how the electrons are arranged in this shells. In the first shell or the nearest shell which is called 'K' can hold up to 2 electrons.

So now after placing 2 electrons in the first shell, we have (10-2), that is 8 electrons left to place in to the shells in correct order. Now let us move to the next shell which is also known as 'L' shell have a maximum capacity of 8 electrons and we have only 8 electron left with us to place. We put the rest of electrons in 'L' shell. This is how the 10 electrons of neon are arranged in shells.

Neon's total electron = 10
Arrangement : K = 2, L = 8

Note :- Electrons revolve around the nucleus in fixed orbits or shells called energy levels.

Now, let us talk about another noble gas which is argon and it have 18 electrons. For arranging we will do the same. In the first shell we will place 2 out of 18 electron, we will now have 16 electron out of which we will place 8 electrons at the second shell and now we have another 8 electrons which we will put at the third shell which is the 'M' shell. So therefore we have -

Argon's total electron = 18
K = 2, L = 8, M = 8

So you will notice that even at the outer shell of argon we see that there are 8 electrons, in fact all noble gases except helium have 8 electrons in their outer shell, this is because of their inert nature. We will see that except noble gases all the other elements are losing, gaining or shared electrons to get 8 electrons in their last shell so to gain a stable position like noble gases. This gaining of 8 electrons in the last shell is called octet rule. The possessing of 8 electrons in the outermost shell of an atom to make the shell fully filled is called as octet or octet rule. But hydrogen which have 1 electron will not try to make 8 electron in its last shell but it will try to make 2 electrons. So, the outermost shell with two electrons is known as a duplet or duplet rule.

Now we will discuss about the other element like how they share or losses or gains electrons by showing it in shells diagrams.

Now let us take sodium which has 11 electrons. So we know that in the first shell we will have 2 electrons and in the second we will have 8 electrons. but sodium have 11 electrons, so the last electron will be placed at the third shell.

So you will notice that the last shell has 1 electron, so for gaining octet state it will need to lose 1 electron or gain 7 more electron to have a octet state. So for losing or gaining electrons energy is needed. Now say for 1 electron 1 Joule of energy is needed. So will you waste 7 joules for gaining electrons or 1 joule to remove 1 electron. Remember we need to choose the option that takes the least energy. So you will obviously choose the option to remove 1 electron instead of gaining 7 electrons. So after removing 1 electron from sodium, our last shell will be 'L' shell which has 8 full electrons. Therefore now it has gained a stable configuration.

We should remember that when we remove electrons we give '+' sign and then write the number of electrons which are removed and vice versa for gaining electron. We have write this whole thing on the top right of the element symbol. Like we have sodium here, so after losing we will write sodium as - Na⁺

Now let us take the example of chlorine. So chlorine's atomic number is 17. So now at 'K' shell 2 electrons will be placed and another 8 electrons will be placed at 'L' shell and at last 7 electrons will be placed at the last shell which is 'M' shell.

Like the previous we will choose that which process takes lesser energy. Here gaining 1 electron needs less energy than losing 7 electrons. Therefore, we will write chlorine as Cl^- as it needs one electron.

Now let's us analysis the two example, one needs and electron and one wants to give one electron. Since we know that opposite charges attract each other, therefore Na⁺ will attract Cl^- ,so the formation will be - The 1 electron of neon will be included into the last shell of 7 electron of chlorine then these two can co-operate each other and can be more stable which makes a compound called 'NaCl'. So the chemical formula is

Na⁺ + Cl^- -----> NaCl

In the above picture the remaining electron is transferred from 'Na' to 'Cl'. This type of compounds are called ionic compounds.

These compounds are called ionic compounds because the metals and non metal attract each other as of the positive and negative ions and when these ions gets attracted to each other (because opposite powers attracts each other) then they form ionic compounds like NaCl.

For concept clearance watch the video -

ASSIGNMENTS

There are three assignment based on how much you have learnt after completing the last assignment that was given.

• Click here for assignment 8
• Click here for assignment 9

QUIZ

You have reached so far to quiz 2. For doing quiz 2 click here.

OCCURANCE OF METALS

To get a pure form of metal there are some process to extract the pure metal. But before we start we must remember some points -

• Generally metals occurs in combined state.
• The rocks will contain the metal compound we need + some impurities too. This metals compounds are minerals and from this only we can get some profitable metal compounds, which are called ores.

Now in this new area we will study about the extraction process of metals from metal ores and how does it goes into different process. So let us start!

EXTRACTION OF METALS

The extraction of metals refers to the process of obtaining pure metals from their ores or naturally occurring mineral deposits. This process involves various steps, including mining, concentration, and metallurgical processes. Here is an overview of the typical extraction process for metals:

1. Mining: The first step involves locating and extracting the ore from the Earth's crust. Ores are rocks that contain valuable minerals or metals. Mining techniques vary depending on the type of ore and its location. Common mining methods include open-pit mining, underground mining, and placer mining.
2. Concentration: Once the ore is extracted, it usually contains a mixture of minerals and impurities. The next step is to separate the valuable mineral or metal from the rest of the ore through a process called concentration or beneficiation. This is typically achieved through physical and chemical processes such as crushing, grinding, sorting, and sometimes froth flotation or magnetic separation.
3. Roasting and Calcination: Some ores, particularly sulfide ores, may undergo roasting (heating in the presence of air) or calcination (heating in the absence of air) to remove volatile impurities and convert the ore into a suitable form for further processing.
4. Reduction: Most metals are extracted from their ores through reduction processes. Reduction involves the removal of oxygen or other elements from the ore to obtain the metal in its elemental form. Common reduction methods include:
   • Smelting: This involves heating the ore along with a reducing agent (such as carbon or coke) in a furnace. The reducing agent reacts with the oxygen in the ore to produce the metal.
   • Electrolysis: Certain metals, such as aluminum and sodium, are extracted through electrolysis. Electrolysis involves passing an electric current through a molten or dissolved compound of the metal, causing it to break down into its constituent elements.
   • Hydrometallurgical Processes: In some cases, metals are extracted using aqueous solutions and chemical reactions. Leaching involves dissolving the metal from the ore using a suitable solvent, and then recovering the metal from the solution through precipitation or other methods.
5. Refining: The obtained metal from the reduction process may still contain impurities. Refining is the process of purifying the metal further to achieve the desired level of purity. This can involve processes such as electrolytic refining, distillation, and various chemical reactions.
6. Casting and Shaping: Once the metal is sufficiently pure, it can be cast into desired shapes for further use. Casting involves melting the metal and pouring it into molds to create ingots, bars, or other forms.
7. Final Processing: Depending on the intended use of the metal, additional processing steps may be required. These could include alloying (mixing the metal with other elements to improve its properties), heat treatment, machining, and surface finishing.

It's important to note that the extraction process can vary significantly depending on the specific metal, ore type, and technological advancements. Different metals may require unique extraction methods and processes to achieve optimal results. Additionally, environmental considerations and sustainability play a crucial role in modern extraction practices, with efforts focused on minimizing the environmental impact of mining and processing activities.

Now let us see the reduction process a bit closely....

REDUCTION OF METAL ORES

Reducing metals from their ores involves removing oxygen or other elements from the ore to obtain the metal in its elemental form. This reduction process is a key step in the extraction of metals and is often carried out using various techniques. Here are some common methods used to reduce metals from their ores:

1. Smelting: Smelting is a common method used to extract metals from their ores, especially metals that have a relatively high melting point. In smelting, the ore is heated in a furnace along with a reducing agent (such as carbon, coke, or charcoal). The reducing agent reacts with the oxygen in the ore, leading to the formation of carbon dioxide and the reduction of the metal. This process results in the metal collecting at the bottom of the furnace, where it can be collected.
2. Blast Furnace: The blast furnace is a type of smelting furnace used primarily for the extraction of iron from iron ore. It operates on the principle of counter-current flow, where the raw materials (iron ore, coke, and limestone) are charged from the top while hot gases (mainly carbon monoxide) are introduced from the bottom. The carbon monoxide reduces the iron ore to molten iron, which collects at the bottom of the furnace.
3. Reduction by Carbon: Carbon is a commonly used reducing agent in metallurgical processes. It is used to extract metals such as iron, zinc, and lead from their respective ores. The carbon reacts with the oxygen in the ore to form carbon dioxide, leaving behind the purified metal.
4. Hydrogen Reduction: Hydrogen gas can be used as a reducing agent to extract certain metals. This method is particularly useful for metals that have a strong affinity for oxygen and form stable oxides. In hydrogen reduction, the ore is heated in the presence of hydrogen gas, which reacts with the oxygen in the ore to form water vapor, leaving the metal behind.
5. Electrolytic Reduction: Electrolysis is used to extract metals that are highly reactive and difficult to reduce using traditional methods. This process involves passing an electric current through a molten or dissolved compound of the metal. The metal ions migrate to the cathode (negative electrode), where they gain electrons and are reduced to the elemental metal. This method is commonly used for extracting metals such as aluminum and sodium.
6. Thermal Reduction: Some metals can be reduced thermally by heating them in the presence of a suitable reducing agent. For example, iron can be reduced from iron ore using methane gas in a process called direct reduction.
7. Carbothermic Reduction: Carbothermic reduction involves the use of carbon as a reducing agent. This method is used for extracting metals from their oxides. The carbon reacts with the metal oxide to produce carbon dioxide and the pure metal.
8. Electron Beam or Laser Reduction: Advanced technologies like electron beams or lasers can be used to provide the energy needed for reduction. These methods are used in specialized applications and research settings.

The choice of reduction method depends on factors such as the type of ore, the metal being extracted, the purity required, and the specific properties of the metal and its compounds. Additionally, advancements in technology and a focus on sustainability continue to influence the development of new and more efficient reduction methods.

ELECTROLYTIC REFINING OF METAL

Before enter let us get a quick small understanding of this topic. Electrolytic refining is a process of refining a metal (mainly copper) by the process of electrolysis. As far as the mechanism of the process is concerned, during electrolysis, a large chunk or slab of impure metal is used as the anode, with a thin strip of pure metal as the cathode....

Electrolytic refining is a process used to purify metals obtained from various sources, such as ores or recycled materials. It involves the use of electrolysis, which is the passage of an electric current through a solution (electrolyte) containing dissolved metal ions. This process is particularly useful for refining metals that are already in a relatively pure state but may contain impurities that need to be removed to achieve a higher level of purity. The electrolytic refining process is commonly used for refining metals like copper, silver, gold, and aluminum. Here's how it works:

1. Setup: The process involves setting up an electrolytic cell consisting of an anode (positive electrode) and a cathode (negative electrode) submerged in an electrolyte solution. The impure metal to be refined is usually used as the anode, while a pure metal or inert material is used as the cathode. The electrodes are connected to a power supply (direct current) that provides the necessary electric current for the process.
2. Electrolyte: The electrolyte is a solution containing a compound of the metal to be refined. For example, in the electrolytic refining of copper, the electrolyte is typically a solution of copper sulfate (CuSO4).
3. Anode Dissolution: At the anode, the impure metal (e.g., impure copper) is oxidized, forming metal ions that go into the electrolyte. For example, in the case of copper refining, copper atoms at the anode lose electrons and become copper ions, entering the electrolyte as Cu²⁺ ions.Cu(s) → Cu²⁺(aq) + 2e⁻
4. Cathode Deposition: At the cathode, metal ions from the electrolyte are reduced, depositing pure metal onto the cathode. In the case of copper refining, copper ions from the electrolyte are reduced at the cathode, forming a layer of pure copper metal.Cu²⁺(aq) + 2e⁻ → Cu(s)
5. Impurity Removal: As the metal ions from the anode enter the electrolyte, impurities in the original metal settle at the bottom of the cell as anode mud or slime. These impurities can include metals that were present in the original impure metal.
6. Control and Monitoring: The process is carefully controlled to ensure that the desired metal is being deposited onto the cathode. Factors such as current density, voltage, temperature, and electrolyte composition are monitored and adjusted as needed to optimize the refining process.
7. End Result: The result of the electrolytic refining process is a cathode made of highly pure metal that has been separated from its impurities. This cathode can then be collected and used for various applications.

Electrolytic refining is an effective method for achieving high levels of metal purity and is widely used in industries where the quality of the metal is crucial, such as in electronics, jewelry, and other high-tech applications.

Now for better understanding see the video-

Khan academy video (short explanation of previous steps + brief explanation of this last step..) -

ASSIGNMENTS

There are three assignment based on how much you have learnt after completing the last assignment that was given.

• Click here for assignment 10
• Click here for assignment 11

CORROSSION

Corrosion is a natural process that involves the deterioration of materials, usually metals, due to chemical reactions with their environment. It is a widespread and often unwanted phenomenon that can lead to the degradation of materials, structural damage, and economic losses. Corrosion occurs when metals react with substances in their surroundings, such as water, oxygen, acids, and salts. The most common type of corrosion is the reaction of metals with oxygen in the presence of moisture, which forms metal oxides or hydroxides.

Here are some key points about corrosion:

1. Prevention and Control: Corrosion can be managed through various methods, including:
   • Coatings: Applying protective coatings such as paints, varnishes, or corrosion-resistant metals (e.g., galvanization).
   • Inhibitors: Introducing chemicals that slow down or prevent the corrosion reaction.
   • Cathodic Protection: Connecting the metal to a sacrificial anode (a more easily corroded metal) to protect the main metal from corrosion.
   • Material Selection: Choosing corrosion-resistant metals or alloys for specific applications.
   • Design Modifications: Designing structures to minimize water entrapment, crevices, or areas prone to corrosion.
   • Proper Maintenance: Regular inspection, cleaning, and maintenance to identify and address corrosion early.
2. Importance: Corrosion can have significant economic and safety implications. It can weaken structures, reduce the lifespan of equipment, and cause failures in critical systems such as pipelines, bridges, and aircraft. Corrosion-related costs, including maintenance, repair, and replacement, are substantial.
3. Examples: Some metals, like iron, are highly susceptible to corrosion, resulting in the formation of rust (iron oxide). Other metals, such as aluminum and stainless steel, have a natural protective layer that can mitigate corrosion. Precious metals like gold and platinum are highly resistant to corrosion.

Understanding the causes and mechanisms of corrosion is essential for developing effective strategies to prevent, control, and mitigate its effects on various materials and structures.

METALS USED IN ALLOYS

Metals are often combined to create alloys, which are materials with improved properties compared to their individual constituent elements. Alloys are widely used in various industries and applications due to their desirable combinations of strength, hardness, corrosion resistance, conductivity, and other characteristics. Here are some common metals used in alloys:

1. Steel: Steel is an alloy of iron and carbon, with varying amounts of other elements like manganese, chromium, nickel, and more. It is one of the most versatile and widely used alloys, known for its strength, durability, and relatively low cost. Different types of steel, such as stainless steel, tool steel, and high-strength steel, are created by adjusting the alloying elements.
2. Stainless Steel: Stainless steel is an alloy of iron, chromium, and often nickel or other elements. It is highly resistant to corrosion and staining, making it ideal for applications where hygiene and durability are important, such as kitchen appliances, medical equipment, and architecture.
3. Aluminum Alloys: Aluminum is often alloyed with other elements such as copper, zinc, magnesium, and manganese to create aluminum alloys with various properties. These alloys are lightweight, corrosion-resistant, and used in a wide range of applications including aircraft, automotive parts, and construction materials.
4. Copper Alloys: Copper alloys include brass (copper and zinc), bronze (copper and tin), and others like cupronickel (copper and nickel) and bronze (copper and aluminum). These alloys are valued for their electrical conductivity, corrosion resistance, and attractive appearance. They are used in electrical wiring, plumbing, musical instruments, and artistic sculptures.
5. Titanium Alloys: Titanium alloys are known for their high strength-to-weight ratio, corrosion resistance, and biocompatibility. They are used in aerospace applications, medical implants, and sporting equipment.
6. Nickel Alloys: Nickel alloys contain significant amounts of nickel along with other elements such as chromium, iron, and molybdenum. They are resistant to corrosion, heat, and high-stress conditions, making them suitable for applications in chemical processing, turbines, and nuclear reactors.
7. Brass: Brass is an alloy of copper and zinc, and its properties can be adjusted by varying the proportions of these two metals. Brass is valued for its malleability, corrosion resistance, and attractive gold-like appearance. It is used in decorative items, musical instruments, and plumbing fittings.
8. Bronze: Bronze is an alloy of copper and tin, but other elements like aluminum, silicon, and phosphorus can also be added. Bronze is known for its hardness, durability, and resistance to corrosion. It has been used historically for statues, coins, and tools.
9. Magnesium Alloys: Magnesium alloys are lightweight and have good strength-to-weight ratios. They are used in applications where weight reduction is critical, such as in aerospace components and lightweight automotive parts.
10. Lead Alloys: Lead alloys, such as solder (lead and tin), are used for their low melting points and ability to bond to other metals. Solder is commonly used in electronics and plumbing.

These are just a few examples of the many alloys that are used in various industries and applications. The choice of alloy depends on the specific requirements of the application, including desired properties, environmental conditions, and cost considerations.

ASSIGNMENTS

There are three assignment based on how much you have learnt after completing the last assignment that was given.

• Click here for assignment 12
• Click here for assignment 13

END OF THE CHAPTER