CBSE Class 10 Science Metals And Non Metals Notes Set 02

Physical Properties of Metals

Metals are the elements that conduct heat and electricity and are malleable and ductile. Examples are Iron (Fe), Aluminum (Al), Silver (Ag), Copper (Cu), Gold (Au), Platinum (Pt), Lead (Pb), Potassium (K), Sodium (Na), Calcium (Ca) and Magnesium (Mg) etc.

Physical Properties of 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).
* State: Metals are solid at room temperature except for mercury (Hg).
* Sound: 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. This is the cause that electric wires are made of metals like copper and aluminum.
* Malleability: Metals are malleable. This means metals can be beaten into a thin sheet. Because of this property, iron is used in making big ships.
* 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. But gold and copper are exceptions.

Chemical Properties of Metals

1. Reaction with oxygen: Most of the metals form respective metal oxides when reacting with oxygen.
Metal + Oxygen → Metal Oxide
Examples:
Reaction of Potassium with Oxygen: Potassium metal forms potassium oxide when reacts with oxygen.

Chemical Properties of Metals

1. Reaction with oxygen: Most of the metals form respective metal oxides when reacting with oxygen.
Metal + Oxygen → Metal Oxide
Examples:
Reaction of Potassium with Oxygen: Potassium metal forms potassium oxide when reacts with oxygen.

Hydrogen (H₂) gas is not evolved when metal is treated with nitric acid (HNO₃):
Nitric acid is strong oxidizing agent and it oxidizes the hydrogen gas (H₂) liberated into water (H₂O) and itself get reduced to some oxide of nitrogen like nitrous oxide (N₂O)₃ nitric oxide (NO) and nitrogen dioxide (NO₂).
Copper, gold, silver are known as noble metals. These do not react with water or dilute acids.
The order of reactivity of metal towards dilute hydrochloric acid or sulphuric acid is in the order;
K > Na > Ca > Mg > Al > Zn > Fe > Cu > Hg > Ag

AMPHOTERIC OXIDE :Those metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. eg. Aluminum oxide and zinc oxide

Reactivity Series of Metals: The order of intensity or reactivity of metal is known as Reactivity Series. Reactivity of elements decreases on moving from top to bottom in the given reactivity series.

In the reactivity series, copper, gold, and silver are at the bottom and hence, least reactive. These metals are known as Noble metals. Potassium is at the top of the series and hence, most reactive.
Reactivity of some metals are given in descending order:
K > Na > Ca > Mg > Al > Zn > Fe > Pb > Cu

Ionic Bonds: Ionic bonds are formed because of transfer of electrons from metal to non-metal.eg. NaCl

Properties of Ionic compound
• Ionic compounds are solid. Ionic bond has a greater force of attraction because of which ions attract each other strongly. This makes ionic compounds solid.
• Ionic compounds are brittle.
• Ionic compounds have high melting and boiling points because force of attraction between ions of ionic compounds is very strong.
• Ionic compounds generally dissolve in water.
• Ionic compounds are generally insoluble in organic solvents; like kerosene, petrol, etc.
• Ionic compounds do not conduct electricity in the solid state.
• The solution of ionic compounds in water conduct electricity. This happens because ions present in the solution of ionic compound facilitate the passage of electricity by moving towards opposite electrodes.
• Ionic compounds conduct electricity in the molten state.