Metal and Nonmetal (Class 10)

Introduction to Metal and Non-metal with their physical and chemical properties

1. Metals and Non-metals Dr. Pranabjyoti Das

2. What are metals…. A metal (Greek métallon ) is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance and conducts electricity and heat relatively well. 05-May-21 2 Pranabjyoti Das

3. Non-Metals Non-metals are natural materials that do not conduct heat or electricity and are structurally brittle so they can not be easily rolled, molded or pressed. 05-May-21 3 Pranabjyoti Das

4. Elements are of three types… Metals Non-metals Metalloids Metalloids possess both the properties of metals as well as non-metals . Eg : S ilicon , G ermanium, A ntimony , etc. 05-May-21 4 Pranabjyoti Das

5. Properties of metals A physical property is any property that is measurable, whose value describes a state of a physical system. The typical physical properties of metals are : 1. High melting points 2. Good conductors of electricity 3. Good conductors of heat 4. High density 5. Malleable 6. Ductile 7. Sonorous 05-May-21 5 Pranabjyoti Das

6. Metals - Physical properties Solids : Metals are solid a t room temperature . ( Exceptions : Mercury and gallium are in liquid state at room temperature ) Lustre : Metals s hine in their pure state or when polished they give a highly reflective surface Malleability : Metals C c n be made into thin sheets 05-May-21 6 Pranabjyoti Das

7. 4. Ductility : Metals can be d rawn into thin wires . Gold & silver are the most ductile metals. One gram of gold can be drawn into a wire of 2 km length 5. Conduction of heat : Metals are g ood conductors of heat and have high melting points. Silver and copper are the best conductors of heat while Lead and mercury are the poor est conductors of heat 6. Conduction of electricity : Metals are g ood conductors of electricity. Electric wires are made of Cu having a n outer insulation of PVC (polyvinyl chloride) METALS : PHYSICAL PROPERTIES 05-May-21 7 Pranabjyoti Das

8. Hardness : Metals are hard but it differs from metal to metal . Alkali metals like S odium and P otassium are soft . They can be cut easily with a knife Melting point and Boiling point of metals are h igh. Tungsten and W olfram have highest melting point s while sodium and potassium have low est melting points Sonorous : Metals can p roduce metallic sound on striking . For example, School bells METALS : PHYSICAL PROPERTIES 05-May-21 8 Pranabjyoti Das

9. Non-Metals The non-metals are the elements that have typically have low melting and boiling points, bad conductors of heat and electricity and tend to have high ionization energies and electro- negativie values. They also don't have the shiny "metallic" appearance associated with the metals. Non-metals have some physical properties… 05-May-21 9 Pranabjyoti Das

10. The typical physical properties of non-metals are : 1. Low melting points 2. Poor conductors of electricity 3. Poor conductors of heat 4. Low density 5. Non-malleable 6. non-ductile 7. Non-sonorous Physical Properties 05-May-21 10 Pranabjyoti Das

11. Physical properties Non-metals exist either in solid or in gaseous state. Exception: Bromine is a liquid non-metal. Non-metals do not have luster. Exception: Iodine. Non-metals are soft and usually have low density. Exception: Carbon in the form of diamond is the hardest substance known which also has a high melting and boiling point. Non-metals are bad conductors of electricity. Exception : Graphite (allotrope of carbon) 05-May-21 11 Pranabjyoti Das

12. Thus we have seen that there are some physical differences between Metal and Non-metal. On the other hand, there are exceptions in each of the physical properties of metals. Yet, on the basis of physical properties the differences between Metal and Non-metal are given below : Difference between Metal & Non-metal 05-May-21 12 Pranabjyoti Das

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14. Since there are exceptions in each of the physical properties of Metal and Non-metal, it is difficult to differentiate Metals from the Non-metals So, elements can be classified more clearly as Metals and Non-metals on the basis of their chemical properties only. Chemical Properties of Metals & Non-metals (Next Class) 05-May-21 14 Pranabjyoti Das

15. Thank You Dr. Pranabjyoti Das Arunodoi Junior College Tangla 05-May-21 15 Pranabjyoti Das