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?
Answer
a. Y and Z
b. W is bigger
Reason: Down the group number of shells increases
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
