Q16 of 31 Page 198

How does metallic character change when we move

(I) Down a group


(II) Across a period?

Metals have a tendency to lose their valence electrons to form a cation.


(I) Down a group


i. As we move from left to right, a new shell gets added.


ii. The distance between the nucleus and the outer electrons.


iii. As a result, nuclear charge decreases with increase in atomic number.


iv. This decreases the force of attraction of electrons by the nucleus.


v. As a result, the tendency of losing electrons goes on increasing.


vi. Thus, metallic character increases within a group.


(II) Across a period


i. As we move from left to right, nuclear charge increases with increase in atomic number. This increase the force of attraction of electrons by the nucleus.


ii. As a result, the tendency of losing electrons goes on decreasing.


iii. Thus, metallic character decreases within a period.


More from this chapter

All 31 →
14

Identify the element that has the lower Ionization energy in each pair oldie following and mark it with a symbol (3).

(i) Mg or Na


(ii) Li or O


(iii) Br or F


(iv) K or Br

 15

In period 2, element X is to the right of element Y. Then, find which of the elements have:

(i) Low nuclear charge


(ii) Low atomic size


(iii) High ionization energy


(iv) High electro negativity


(v) More metallic character

 17

Why was the basis of classification of elements changed from the atomic mass to the atomic number?

 18

What is a periodic property? How do the following properties change in a group and period? Explain.

(a) Atomic radius


(b) Ionization energy


(c) Electron affinity


(d) Electro negativity.


(b) Explain the ionization energy order in the following sets of elements:


a) Na, Al, Cl b) Li, Be, B


c) C N, O d) F, Ne, Na c) Be, Mg, Ca