CBSE Class 10 Chemistry Metals and Non Metals Worksheet Set B

Metals and Non-Metals Notes Class 10 Science

Physical Properties of Metals
● Hard and have a high tensile strength – Carbon is the only non metal with very high tensile strength.
● Solid at room temperature – One non-metal, bromine, is a liquid at room temperature. The other nonmetals are solids at room temperature, including carbon and sulfur.
● Sonorous – Metals produce a typical ringing sound when hit by something.
● Good conductors of heat and electricity – Graphite is good conductor 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 Caesium (Cs) and Gallium (Ga)) – Graphite, a form of carbon (a non-metal), has a high boiling point and exists in the solid state at room temperature.
● Dense, (except alkali metals). Osmium – highest density and lithium – least density
● Lustrous – Metals have the quality of reflecting light from their surface and can be polished e.g., gold, silver and copper. Iodine and carbon are non-metals which are lustrous. Note that carbon is lustrous only in certain forms like diamond , and graphite.
● Silver-grey in colour, (except gold and copper) – Metals usually have a silver or grey colour.

Physical Properties of Non-metals
Occur as solids, liquids and gases at room temperature
Brittle
Non-malleable
Non-ductile
Non-sonorous
Bad conductors of heat and electricity

Chemical Properties of Metals
● Alkali metals (Li, Na, K, etc) react vigorously with water and oxygen or air.
● Mg reacts with hot water.
● Al, Fe and Zn react with steam.
● Cu, Ag, Pt, Au do not react with water or dilute acids.
Reaction of Metals with Oxygen (Burnt in Air)
Metal oxide is formed when metals are burned in air and react with oxygen in the air. Metal oxides are a type of basic material found in nature.
Metal + Oxygen→ Metal oxide (basic)
● Na and K are kept immersed in kerosene oil as they react vigorously with air and catch fire.
4K(s)+O2(g)→2K₂O(s) (vigorous reaction)
● Mg, Al, Zn, Pb react slowly with air and form a protective layer that prevents corrosion.
2Mg(s)+O₂(g)→2MgO(s) (Mg burns with white dazzling light)
4Al(s)+3O₂(g)→2Al₂O₃(s)
● Silver, platinum and gold don’t burn or react with air.

Reactivity Series
The reactivity series of metals, also known as the activity series, refers to the arrangement of metals in the descending order of their reactivities.
Reaction of Metals with Water or Steam
Aluminium, iron, and zinc are metals that do not react with either cold or hot water. However, when they come into contact with steam, they produce metal oxide and hydrogen. Lead, copper, silver, and gold are metals that do not react with water.
Metal+Water→Metalhydroxide or Metaloxide+Hydrogen

Reaction of Metals with Acid
When a metal is immersed in acid, it becomes smaller and smaller as the chemical process consumes it. Gas bubbles can also be detected at the same moment. Hydrogen gas bubbles are formed as a result of the reaction. Because hydrogen is combustible, this can be demonstrated with a burning splint.
Metal+ dilute acid→Salt+ Hydrogengas
2Na(s)+2HCl(dilute)→2NaCl(aq)+H₂(g)

Reaction of Metals with Bases
The base has a bitter taste and a slippery texture. A base dissolved in water is called an alkali. When chemically reacting with acids, such compounds produce salts. Bases are known to turn blue on red litmus paper.
Base+ metal → salt+ hydrogen

Reaction Of Non-Metals with Oxygen
Non-Metals react with oxygen to form acidic oxides or neutral oxides. Carbon form an acidic oxide carbon dioxide. Sulphur form an acidic oxide sulphur dioxide. Hydrogen form a neutral oxide water. The acidic oxides of non-metals turn blue litmus solution to red.
C(s) + O₂ (g) ——> CO₂ (g)
CO₂ (g) + H₂0 (l) —–> H₂CO₃ (aq)
S (s) + O₂ (g) ——> SO₂ (g)
SO₂ (g) + H₂0 (l) —–> H₂SO₃ (aq)

Reaction of non-metal with water
They do not react with water to evolve hydrogen gas.

Reaction of non-metals with acids
They do not react with dilute acids. They do not displace hydrogen from acids.

Reaction of Non-metals with salt solution
A more reactive non-metal displaces a less reactive non-metal from its salt solution.

Reaction of Non-metal with chlorine
Non-Metals react with chlorine to form covalent chlorides which are non-electrolytes.

Reaction of Non-metals with hydrogen
Non-Metals react with hydrogen to form covalent hydrides.

Extraction of metals
Thermite reaction: Al(s)+Fe₂O₃(s) → Al₂O₃+Fe(molten)
The thermite reaction is used in welding of railway tracks, cracked machine parts, etc.

Occurrence of Metals
Most of the elements, especially metals occur in nature in the combined state with other elements. All these compounds of metals are known as minerals. But out of them, only a few are viable sources of that metal.
Such sources are called ores.
Au, Pt – exist in the native or free state.
Metals of high reactivity – Na, K, Mg, Al.
Metals of medium reactivity – Fe, Zn, Pb, Sn.
Metals of low reactivity – Cu, Ag, Hg
Enrichment of Ores It means the removal of impurities or gangue from ore, through various physical and chemical processes.

The technique used for a particular ore depends on the difference in the properties of the ore and the gangue.
Extracting Metals Low in Reactivity Series By self-reduction- when the sulphide ores of less electropositive metals like Hg, Pb, Cu etc., are heated in air, a part of the ore gets converted to oxide which then reacts with the remaining sulphide ore to give the crude metal and sulphur dioxide. In this process, no external reducing agent is used.

1. 2HgS(Cinnabar)+3O₂(g)+heat→2HgO(crude metal)+2SO₂(g)
2HgO(s)+heat→2Hg(l)+O₂(g)

2. Cu₂S(Copperpyrite)+3O₂(g)+heat→2Cu₂O(s)+2SO₂(g)
2Cu₂O(s)+Cu₂S(s)+heat→6Cu(crude metal)+SO₂(g)

3. 2PbS(Galena)+3O₂(g)+heat→2PbO(s)+2SO₂(g)
PbS(s)+2PbO(s)→2Pb(crudemetal)+SO₂(g)
Extracting Metals in the Middle of Reactivity Series

Calcination is a process in which ore is heated in the absence of air or air might be supplied in limited quantity. Roasting involves heating of ore lower than its melting point in the presence of air or oxygen.
Calcination involves thermal decomposition of carbonate ores.

Smelting – it involves heating the roasted or calcined ore (metal oxide) to a high temperature with a suitable reducing agent. The crude metal is obtained in its molte
Fe₂O₃ + 3C(coke)→ 2Fe + 3CO₂

Extraction of Metals Towards the Top of the Reactivity Series

Electrolytic reduction:
Down’s process: Molten NaCl is electrolysed in a special apparatus.
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.

The metals at the top of the reactivity series are highly reactive. They cannot be obtained from their compounds by heating with carbon, because these metals have more affinity fo for oxygen than carbon. Hence, for the extraction of such metals electrolytic reduction method is used.

Refining of Metals
Refining of metals – removing impurities or gangue from crude metal. It is the last step in metallurgy and is based on the difference between the properties of metal and the gangue.

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.

How Do Metals and Nonmetals React
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 calcium chloride, the ionic bond is formed by opposite charged calcium and chloride ions.
Calcium atom loses 2 electrons and attains the electronic configuration of the nearest noble gas (Ar). By doing so, it gains a net charge of +2.The two Chlorine atoms take one electron each, thus gaining a charge of -1 (each) and attain the electronic configuration of the nearest noble gas (Ar).

Ionic Compounds
Ionic compounds are neutral compounds that are made up of positively charged cations and negatively charged anions. Binary ionic compounds (ionic compounds containing only two types of elements) are named by first writing the name of the cation, then the name of the anion.
The electrostatic attractions between the opposite charged ions hold the compound together.
Example: MgCl₂, CaO, MgO, NaCl etc.
Properties of Ionic Compound
Ionic compounds
Are usually crystalline solids (made of ions).
Have high melting and boiling points.
Conduct electricity when in aqueous solution and when melted.
Are mostly soluble in water and polar solvents.

Alloys
Alloys are homogeneous mixtures of metal with other metals or nonmetals. Alloy formation enhances the desirable properties of the material, such as hardness, tensile strength and resistance to corrosion.

Examples of a few alloys:

Brass: copper and zinc

Bronze: copper and tin

Solder: lead and tin

Amalgam: mercury and other metal

Corrosion
Gradual deterioration of material usually a metal by the action of moisture, air or chemicals in the surrounding environment.

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

Corrosion of copper:
Cu(s)+H₂O(moisture)+CO₂(from air)→CuCO₃.Cu(OH)₂(green)

Corrosion of silver:
Ag(s)+H₂S(from air)→Ag₂S(black)+H₂(g)

Prevention of Corrosion
1. Coating with paints or oil or grease: Application of paint or oil or grease on metal surfaces keep out air and moisture.
2. Alloying: Alloyed metal is more resistant to corrosion. Example: stainless steel.
3. Galvanization: This is a process of coating molten zinc on iron articles. Zinc forms a protective layer and prevents corrosion.
4. Electroplating: It is a method of coating one metal with another by the use of electric current. This method not only lends protection but also enhances the metallic appearance.
Example: silver plating, nickel plating.
5. Sacrificial protection: Magnesium is more reactive than iron. When it is coated on the articles made of iron or steel, it acts as the cathode, undergoes reaction (sacrifice) instead of iron and protects the articles.

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