Question

122 X Class Classification of Elements - The Periodic Table

A medical shop contains a vast number of medicines. The shop keeper

finds it difficult to remember all the names of medicines that he has. When

you go to a medical shop and ask the shopkeeper for a particular medicine,

he hands over it to you without any difficulty. How is it?

Think of a super bazaar. When you step in to it you see a particular

arrangement of goods inside it. When you look for needed grocery, you

can select it easily.

From the above observations you understand that for any system

involving several things, a particular order of arrangement of those things

is essential.

Even in chemistry, from the earliest times, scientists have been trying

to classify the available elements in to a limited number of groups on the

basis of their properties.

Need for the arrangement of elements in an organised manner

Robert Boyle (1661) defined an element as any substance that cannot

be decomposed into a further simple substance by a physical or chemical

change.

At his time, about thirteen elements were known.

Towards the end of the eighteenth century, by the time of Lavoisier

another eleven elements were discovered. By 1865 about sixty three

elements were known and by 1940, a total of ninety one elements from

natural sources and another seventeen elements synthetically were

obtained.

Classification of Elements-

The Periodic Table

7

Chapter

SCERT TELANGANA​

Answer 1

Answer:

Duy Dec high vgg gudh offer h DJ tak yuvakk go HDD into Garg xx km my Digg j ii an drill

Explanation:

Duy Dec high vgg gudh offer h DJ tak yuvakk go HDD into Garg xx km my Digg j ii an drill