Question

Rank the members of each set of compounds according to the ionic character of their bonds. a. Most ionic bonds? a. PCl3 b. PBr3 c. PF3 Least ionic bonds? a. PCl3 b. PBr3 c.PF3 b.Most ionic bonds? a. BF3 b. NF3 c. CF3 Least ionic bonds?a. BF3 b. NF3 c. CF3 c. Most ionic bonds? a. SeF4 b. TeF4 c. BrF3 Least ionic bonds? a. SeF4 b. TeF4 c. BrF3

Answer 1

Answer: Most ionic bonds:  PF3

Least ionic bonds  PBr3

Most ionic bonds BF3

Least ionic bonds  NF3  

Most ionic bonds TeF4

Least ionic bonds BrF3

Explanation:

In order to classify the type of bond, we calculate the molecule electronegativity by  subtracting the individual electronegativity of each atom.

Keep in mind that a result of 1.7 or more, will let you know that it is an ionic bond ( as you can see in the image)

Let´s check each atom electronegativity: P = 2.1 ;  Cl= 3.0;  Br= 2.8 ; F =4.0  ; B= 2.0;  N=3.0 ;   C=2.5;   Se=2.4 ; Te= 2.1 ;   Br =2.8

Now we start with the first set members : PCl3 = 3.0- 2.1 = 0.9

PBr3 = 2.8- 2.1 = 0.7

PF3= 4.0 - 2.1 = 1.9

as we can see,  PF3 has the higher value of electronegativity, more than 1.7 of electronegativity as we have previously mentioned, means it has more character ionic bond than others.

By substracting electronegativities of each atom, you will realize that is pretty easy to rank any member as more or less electronegative.