SATHEE: Classification of Elements and Periodicity in Properties

Classification of Elements and Periodicity in Properties - Result Question 11

####11. In which of the following options the order of arrangement does not agree with the variation of property indicated against it?

[2016]

(a) $A l^{3 +} < M g^{2 +} < N a^{+} < F^{-}$ (increasing ionic size)

(b) B $<$ C $< N < O$ (increasing first ionisation enthalpy)

(d) $L i < N a < K < R b$ (increasing metallic radius)

Show Answer

Solution:

(b) The correct order is $B < C < O < N$

Generally ionisation energy increases across a period. But here first I.E. of O is less than the first I.E. of N. This is due to the half-filled $2 p$ orbital in $N (1 s^{2}, 2 s^{2}, 2 p^{3})$ which is more stable than the $2 p$ orbital in $O (1 s^{2}, 2 s^{2}, 2 p^{4})$ .

Halogens have high electron affinities which decreases on moving down the group. However, fluorine has lower value than chlorine which is due to its small size and repulsion between the electron added and electrons already present.

Classification of Elements and Periodicity in Properties - Result Question 11

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Classification of Elements and Periodicity in Properties - Result Question 11

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Menu