Tiêu đề Chapter 3 Metals and Non Metals.pdf ✅

SCIENCE (Chemistry) Chapter 3: Metals & Non-Metals
(1) 03 METALS & NON-METALS Metals & Non-Metals Physical Properties of Metals ● Physical State: With the exception of mercury and gallium, which are liquids at room temperature, metals are solids at room temperature. ● Lustre: The property of metals which makes the light reflect from their surfaces is called lustre. This property of the metals can be due to the polished metal surfaces. Eg., gold and silver. ● Malleability: Metals may be formed into thin sheets known as foils and can withstand hammering. With the exception of Zinc, which is fragile. ● Ductility: Wires can be made out of metals. With the exception of Zinc, which is fragile. ● Hardness: Except for sodium and potassium, which are soft and can be cut with a knife, all metals are hard. ● Conduction: Because metals have free electrons, they are good conductors. Silver and copper are the best heat and electricity conductors. Lead is the least efficient heat conductor. Iron, bismuth, and mercury are likewise poor conductors. ● Density: Metals have a high density and weigh a lot. The densities of iridium and osmium are the greatest, whereas lithium has the lowest density. ● Melting and Boiling Point: Metals are known for their high melting and boiling points. The melting point of tungsten is the highest, while the boiling point of silver is the lowest. The melting values of sodium and potassium are both low. ● Alloy Formation: Metals combine to create an alloy, which is a homogeneous combination of metals. Brass is a copper and zinc alloy. ● Sonorous: Metals, when hit by a solid object, produce sound. This property of a metal is known as sonorous. Physical Properties of Non-Metals
(2) 03 METALS & NON-METALS ● Physical State: At ambient temperature, the majority of non-metals exist in two of the three states of matter: gases (oxygen) and solids (iodine, carbon, sulphur). There is no metallic sheen to them (save iodine) and they do not reflect light. (With the exception of carbon in the form of diamond.) ● Nature: Non-metals are extremely fragile, and they can't be coiled into wires or hammered into sheets. Except for diamond, which is the world's hardest substance. ● Conduction: Non-metals are poor heat and electrical conductors. (Except graphite conducts heat, both graphite and gas carbon conduct electricity.) ● Electronegative Character: Non-metals have a proclivity for gaining or sharing electrons with neighbouring atoms. Hence, non-metals are known for their electronegative nature. ● Reactivity: When they come into contact with oxygen, they produce acidic or neutral oxides. Hence, non-metals are reactive. ● Melting and Boiling Points: Non-metals are known for its low melting and boiling points. Difference in Physical Properties of Metals and Non-Metals: Metals Non-metals 1. Metals are good conductors of heat and electricity. 1. Non-metals are bad conductors of heat and electricity. 2. Metals are malleable that is they can be beaten into sheets. 2. Non-metals are not malleable. 3. Metals are ductile that is they can be drawn into wires. 3. Non-metals are not ductile. 4. Metals are sonorous. 4. Non-metals are not sonorous. 5. Metals have high tensile strength due to high attraction between molecules. 5. Non-metals have low tensile strength due to low attraction between molecules. 6. Metals have high density. 6. Non-metals have low density.
(3) 03 METALS & NON-METALS Metals are good conductors of heat. Metals are good conductors of electricity Chemical Properties of Metals Reaction of Metals are burnt in Air (with Oxygen) Almost all metals react with oxygen to form metal oxides. Metal + Oxygen → Metal oxide (basic) ● Sodium and potassium are the most reactive and react with oxygen present in the air at room temperature to form the oxides. It is kept immersed in kerosene oil as they react vigorously with air and catch fire. 4K(s)+O2(g) → 2K2O(s) (vigorous reaction) ● Magnesium does not react with oxygen at room temperature, but on heating, it burns in the air with intense light and heat to form magnesium oxide. 2Mg(s)+O2(g) → 2MgO(s) (Mg burns with white dazzling light) ● Silver, platinum and gold don’t burn or react with air. Reaction of Metals with Water Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal hydroxide. But all metals do not react with water. Metal + Water → Metal oxide + Hydrogen Metal oxide + Water → Metal hydroxide