Class - X science chapter - Metals and non Metals

 ~CHAPTER AT A GLANCE ▪︎

1).Metals : metals show metallic

 lustre, are generally hard,malleable  

and ductile. They are good

conductors of heat and electricity. 

 

2).Metals are sonorous : metals

produce a sound when they strike a

hard surface. We Express it by

saying that metals are sonorous.

That it why school bells are made of 

metals. 

3). Non metals : substances like

carbon, sulphur and iodine are non

metals. They are either solid or gas

with the exception of bromine which

is liquid. 

4).Exceptions : 

(i) Metals in general have high

melting points. But mercury, gallium

and Celsium have low melting points

and are liquids at room

temperature.

(ii) Iodine, a non-metal, show lustre.

(iii) Diamond, an allotrope of carbon,

is the hardest natural substance

known. Graphite, another allotrope

of carbon, is a conductor of

electricity. 

Elements can be classified as metals and non-metals on the basis of their chemical properties

Metal... 

5). The Reactivity Series : It is a list of

metals arranged in decreasing order of

reactivity..

      Activity series or relative reactivites of metals.

K                potassium          most reactive 

Na                Sodium                  

Ca               Calcium

Mg              Magnesium 

Al                Aluminium

Zn               Zinc                Reactivity decreases        

Fe                 Iron

Pb                Lead

H                  Hydrogen 

Cu                Copper 

Hg                Mercury 

Ag                 Silver 

Au                 Gold                Least 

 

6). Reaction of metals with oxygen :

magnesium burns in air easily to

produce magnesium oxide. But not

all metals combine with oxygen

easily. Some metals require heating

for combination with oxygen. 

For example :        

                       2Cu +O/2  ----❯ 2CuO

                                         Copper (II) oxide 

                                            Black

              

                     4Al +3o/2 ----❯ 2Al/2o/3 

                                        Aluminium oxide

7). Amphoteric oxides : some metal

oxides such as aluminium oxide

and zinc oxide show both acidic as

well as basic behaviour. Such metal

oxides react with both acids as well

as bases to produce salt and water.

Such oxides are known as

amphoteric oxides. This is

 illustrated by taking the example

of aluminium oxide. 

      Al/20/3 + 6HCI ----❯ 2AICI/3 + 3H/2O 

  Al/20/3 + 2NaOH -----❯ 2NaAlO/2+H/2O

  

                                   (Sodium aluminate)

8). It is observed that lead, copper, silver and gold do not react with cold water or hot water or steam.