Q22 of 60 Page 138

Study the Periodic Table and answer the following questions:

(i) Na has physical and chemical properties similar to which element(s) and why?


(ii) Write the electronic configuration of N and P. Which one of these will be more electronegative and why?


(i) Na has similar properties as of the same group members as K, Rb, Cs. They contain 1 valence in the outermost shell so all of them are reactive.

(ii) Nitrogen:- 2,5


Phosphorus:- 2,8,5


Electronegativity is a measure of how strongly atoms attract bonding electrons to themselves.


Nitrogen is more electronegative because in nitrogen outermost shell is nearer to nucleus and nucleus will attract electrons easily.


More from this chapter

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20

The elements of the 3rd period of the periodic table are given along:

Na Mg Al Si P S Cl


(a) Which is more non-metallic S or Cl?


Na Mg Al Si P S Cl


(b) Which has a higher atomic mass: Al or Cl?

 21

What physical and chemical properties of elements were used by Mendeleev in creating his Periodic Table? List two observations which posed a challenge to Mendeleev’s Periodic Law.

 23

Using the above periodic table Explain why:

(i) Li and Na are considered as active metals.


(ii) Atomic size of Mg is less than that of the Na.


(iii) F is more reactive than Cl.

 24

Explain giving a reason, why:

(i) Metallic character decreases in a period.


(ii) Atomic size increases in a group.


(iii) Chemical reactivity first decreases and then increases in a period.