YES Bank ATM - Agra

Fine working

good service

Only branch in dayal Bagh

This is on the main dayalbagh to bhagwan talkies road near bhagat halwai heera bagh

Have you seen wooden bells in temples? Can you give a reason? The things made of metals produce a ringing sound when struck hard. Suppose you have two boxes similar in appearance, one made of wood and the other of metal. Can you tell which box is made of metal by striking both the boxes? Since metals produce ringing sounds, they are said to be sonorous. The materials other than metals are not sonorous. After performing the above activities, we can say that some materials are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity. The materials which generally possess these properties are called metals. The examples of metals are iron, copper, aluminium, calcium, magnesium, etc. In contrast, materials like coal and sulphur are soft and dull in appearance. They break down into a powdery mass on tapping with a hammer. They are not sonorous and are poor conductors of heat and electricity. These materials are called non-metals. The examples of non-metals are sulphur, carbon, oxygen, phosphorus, etc. which rust is formed. You had also performed in Class VII an activity of burning a magnesium ribbon in air. You had learnt that in both the processes oxide formation takes place. Complete the following reactions of iron and magnesium with oxygen. Iron (Fe) + Oxygen (O2 ) + Water (H2O) → ? Magnesium (Mg) + Oxygen (O2 ) → ? Activity 4.3 Let us check the nature of rust formed as a result of the reaction between iron, oxygen and water. Collect a spoonful of rust and dissolve it in a very little amount of water. You will find that the rust remains suspended in water. Shake the suspension well. Test the solution with red and blue litmus papers (Fig. 4.3). What do you observe? Is the solution acidic or basic? Metals like sodium and potassium are soft and can be cut with a knife. Mercury is the only metal which is found in liquid state at room temperature. These are exceptions. 4.2 Chemical Properties of Metals and Non-metals Reaction with Oxygen You are familiar with the phenomenon of rusting of iron. Recall the reaction by Rust Rust suspension Red litmus paper Fig. 4.3 : Testing the nature of rus