Class 10 ( Metals And Non Metals)

                   METALS AND NON-METALS

                                  CLASS 10

                               CHEMISTRY

Physical properties of metals and non metals :

1. Malleability: Property of a substance due to which it can be beaten into thin sheet. Metals are  malleable while non metals are not.

2. Ductility: Property of a substance by which it can be drawn into into thin wire. Metals are ductile but non metals are not.

3. Conduction of heat : Metals are good conductors of heat. Sliver and copper are best conductors while lead and mercury are poor conductors of heat. Non metals are bad conductor.

4. Conduction of electricity: Metals are good conductor of electricity while Non metals are bad conductor of electricity with an exception of graphite.

5. Appearance of surface : Metals, are in pure state having shining surface also called metallic luster. Non metals are generally non lustrous. with exception of iodine.

6. Hardness : Metals are generally hard with exceptions of sodium and potassium that can be cut by knife.

7. Density: Metals have high density except sodium and potassium.

8. Melting and boiling points : Generally metals have melting and boiling points . except sodium ,potassium, mercury, cesium and gallium.

9. Sonority: Property of producing sound on striking a hard surface . Metals are sonorous whereas non-metals are not.

Chemical property of metals

1. Reaction with oxygen :
Almost all metals combine with oxygen to form metal oxide.
                                   Metal + O2 → Metal oxide
                                    
                                       2Cu + O2 → 2CuO
       
Metal oxide are basic in nature. Some metal oxide, such as aluminum oxide , zinc oxide etc. are react with both acid as well as bases to produce salts and water are known as amphoteric oxides.

2.   Reaction with water:

All metals do not react with water. Those which react and form metal oxide and hydrogen gas. Metal oxides that are soluble in water further formed metal hydroxide.

2Na + 2H2O → 2NaOH + 1H2

2Al + 3H2O → Al2O3 + 3H2

3. Reaction with Dilute acids:

Most metals reacts with acids to give salt and hydrogen gas.

Metal + Acid → Metal Salt + Hydrogen

Mg + 2HCl → MgCl2 + H2

Aquaregia: 

Freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1 .
Is a highly corrosive , fuming liquid and one of the few reagents able to dissolve gold and platinum.

Reactivity of metals / Reactivity Series:



Reaction of Metals with Metal salts: 
Reactive metals can displace less reactive metals from their compounds in solution or molten form.

How do metals and non metals react:

The compounds formed by the transfer of electrons from a metal to a non metal are known as ionic or electrovalent compounds.

Ionic compounds

Ionic compounds are chemical compounds composed of positively charged ions (Cation)  and negatively charged ions .

Ionic bonding is the electrostatic attraction between positively charged ion and negatively charged ion. this attraction holds the ions together in a stable compound.

Properties of ionic compounds:
1. Physical property: solid and hard.

2. They are crystalline in nature.

3. They have strong forces of attraction between the ions. Therefore, the ionic compounds exist in solid state.

4. They have high melting and boiling points.

5. They are good conductors of electricity in the molten state and in aqueous solutions.

6. They are readily soluble in water and insoluble in solvents like Kerosene , petrol etc.

Occurrence of metals

Elements are the building blocks of all matter present in the universe. How do these elements occur in the earth's crust, atmosphere, sea and how are they obtained? Metals account for 80 percent of all known elements, and our primary focus on this topic will be on metal extraction. 

Elements are found in nature either in their free state (native state) or in their combined state, i.e. as compounds. In their natural state, some elements are not easily attacked by moisture, oxygen or carbon dioxide from the air. For example, carbon, gold, platinum and so on. Elements that are easily attacked by moisture, oxygen and carbon dioxide in the air exist in the combined state as minerals, i.e. oxides (e.g.,Fe2O3, Al2O3, MnO2). Furthermore, the majority of metal halides that are soluble in water are found in lakes and seas, whereas the majority of metal oxides and sulphides that are insoluble are found in rock.

ORE

An ore is a mineral from which the metal can be extracted easily and cheaply. All ores are minerals, however, all minerals are not necessary to be ores. Aluminum, for example, is found in the earth's crust as two minerals: bauxite and china clay. Aluminum can be extracted from bauxite simply and cost-effectively, whereas no simple and cost-effective method exists for extracting aluminum from clay. As a result, bauxite is the ore of aluminium.

 

EXTRACTION OF METALS

Let's study the process of extraction of metals from their ores (i.e. metallurgy). The process used to extract a metal is determined by its physical and chemical properties, as well as the impurities associated with it. Since different metals have different physical and chemical properties, they require different extraction methods. There are some procedures and processes for metal extraction. Let's look at some of the methods for ore concentration, which is the first step in metal extraction.

1. Electromagnetic Separation

When the ore or the impurities associated with it are magnetic in nature, this method of concentration is used. The powdered ore is dropped over a conveyor belt, moving around two rollers, one of which contains an electromagnet. The magnetic roller attracts the magnetic particles as the ore particles roll over the belt. As a result, two heaps form independently. The magnetic particles are collected in the heap formed beneath the magnetic roller, while the non-magnetic impurities are collected in the heap formed away from the magnetic roller. In the case of tinstone, the magnetic tungstate's form a heap beneath the magnetic roller, while the ore particles, i.e., SnO, forms a separate heap away from the magnetic roller.

2. Conversion of Concentrated Ore into Metal Oxide

Calcination: This method converts carbonate and hydrated oxide ores to their respective oxides, by heating them to temperatures well below their melting points, either in the absence or with a limited supply of air. Nonmetallic impurities such as S, P, As and others are removed as volatile oxides.

Roasting: By intensely heating sulphides ores, this process converts them to their respective oxides.

Conclusion : The Earth's crust is a repository for metals such as Sulphur and silicon. Some of the major metals, such as chloride, are also reported in seawater. They can be found in both free and combined states. Metallurgy is the sum of all processes used to extract metals from their ores. Ores are minerals from which one or more metals can be extracted easily and profitably. As previously discussed, there are various methods for ore concentration. These include hydraulic, froth flotation, electromagnetic leaching, and other extraction methods.