Q. 6.62 - An Introduction to General, Organic, and Biological Chemistry

Question

Describe the trend in electronegativity as increases or decreases for each of the following: 

(a) from Al to CI 

(b) from Br to K 

(c) from Li to Cs

Step-by-Step Solution

Answer

(a) Electronegativity will increase.

(b) Electronegativity will decrease.

(c)  Electronegativity will decrease. 

Part (a) Step 1: Given Information

We have to find out the effect of electronegativity from Al to Cl.

Part (a) Step 2: Explanation

Moving left to right across the period, the electronegativity increases and

going down the group, the electronegativity decreases.

According to the given question, 

Al is in ${13}^{th}$ group and Cl is in ${17}^{th}$ group. The period is same and this shows that going across the period, electronegativity increases.

Hence, electronegativity will increase.

Part (b) Step 1: Given Information

We have to find out the effect of electronegativity from Br to K.

Part (b) Step 2: Explanation

Moving left to right across the period, the electronegativity increases and

down the group, the electronegativity decreases.

According to the given question, 

Br is in ${17}^{th}$ group and K is in $1^{st}$ group. The period is same and this shows that going across the period from right to left, the electronegativity decreases.

Hence, electronegativity will decrease.

Part (c) Step 1: Given Information

We have to find out the effect of electronegativity from Li to Cs.

Part (c) Step 2: Explanation

Moving left to right across the period, the electronegativity increases and 

going down the group, the electronegativity decreases.

According to the given question, 

Li is in $2^{nd}$ period and  Cs is in $6^{th}$ period. The group is same and this shows that going down the group electronegativity decreases.

Hence, electronegativity will decrease.