Check sibling questions

The diagram below shows part of the periodic table.

a. Which elements would react together to form covalent compounds?

b. Between the two elements W and Z, which will have a bigger atomic radius? Why?

Question 2 - Science Sample Paper - Class 10 Term 2.png

Answer

a. Y and Z

b. W is bigger

Reason: Down the group number of shells increases

Periodic table of elements-01-01.jpg

Explanation

In this question, there are 3 elements ,W,Y and Z

Element W

It lies in second group (Column) of Periodic Table

it means there are 2 Valence Electronic in outermost shell

It needs to loose 2 electrons to form compound

This is not possible in Covalent bonds where atoms share electrons (and not loose them)

Element Y

It lies in Sixth group (Column) of Periodic Table

it means there are 6 Valence Electronic in outermost shell

It needs to gain 2 electrons to form compound

Element Z

It lies in seventh group ( Column) of Periodic Table

it means there are 7 Valence Electronic in outermost shell

It needs to gain 1 electrons to become stable

 

Since Element Y and Z both want to gain electrons, they can share electrons with other to form covalent bonds

So, one Y atom shares its 2 electrons with 2 atoms of Z to achieve inert gas configuration

Since, there is sharing of electron, it is a covalent bond

 

Between the two elements W and Z, which will have a bigger atomic radius? Why?

Explanation

  • As we go down the periodic table, the number of shells increase
  • Due to increase in number of shells, atomic radius also increases

Now, Comparing W and Z

W Z

It lies in fourth period (row)

Hence, it has 4 shells

It lies in second period (row)

So it has 2 shells

 

Since, W has more number of shells, it will have more atomic radius

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