Chapter 18, Problem 44R

To determine

To identify: which of the two possible compounds in the right column of the table below is correct.

Explanation of Solution

Introduction:

The elements from one group of elements combine with the elements of other groups to form polyatomic ions of the same ratio.

The table shows some compounds, so the formation of the possible compound is

Formula	Possible compound	Compound formed
${\text{SF}}_{\text{6}}$	${\text{AlF}}_{\text{6}}$ or ${\text{TeF}}_{\text{6}}$	${\text{TeF}}_{\text{6}}$
${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}$	${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ or ${\text{BaSO}}_{\text{4}}$	${\text{NaSO}}_{\text{4}}$
${\text{CaCO}}_{\text{3}}$	${\text{OCO}}_{\text{3}}$ or ${\text{BaCO}}_{\text{3}}$	${\text{BaCO}}_{\text{3}}$
${\text{CO}}_{\text{2}}$	${\text{CCl}}_{\text{2}}$ or ${\text{CS}}_{\text{2}}$	${\text{CS}}_{\text{2}}$

In the above table, there are one common atom, therefore, another atom decides the formation of a new compound. The atom belonging to the same group will have the same number of valence shell electrons and thus form similar compounds.

1. ${\text{SF}}_{\text{6}}$ contain sulfur and fluorine atoms. Sulfur belongs to group 16. ${\text{AlF}}_{\text{6}}$ contain aluminum and fluorine atom. Aluminum belongs to group 13. ${\text{TeF}}_{\text{6}}$ contains tellurium and fluorine. Tellurium belongs to group 16. Therefore, the compound that matches with the ${\text{SF}}_{\text{6}}$ is ${\text{TeF}}_{\text{6}}$ because both of them belong to the same group.

2. ${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}$ contains potassium and sulfate ions. Potassium belongs to group 1. ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ contain sodium and sulfate ion. Sodium also belongs to group 1. ${\text{BaSO}}_{\text{4}}$ contains barium and sulfate ions. Barium belongs to group 2. Therefore, the compound that matches with ${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}$ is ${\text{NaSO}}_{\text{4}}$ . As both of them belongs to group 1.

3. ${\text{CaCO}}_{\text{3}}$ contains calcium and carbonate ions. Calcium belongs to group 16. ${\text{OCO}}_{\text{3}}$ contain oxygen and carbonate ion. Oxygen belongs to group 16. ${\text{BaCO}}_{\text{3}}$ contain barium and carbonate ions. Barium belongs to group 2.

Therefore, the compound that matches with ${\text{CaCO}}_{\text{3}}$ is ${\text{BaCO}}_{\text{3}}$ .

4. ${\text{CO}}_{\text{2}}$ contains carbon and oxygen atoms. Carbon belongs to group 14 and oxygen belongs to group 16. ${\text{CS}}_{\text{2}}$ contain carbon and sulfur atoms. Sulfur belongs to group 16. ${\text{CCl}}_{\text{2}}$ belongs to group 17.

Therefore, the compound that matches with ${\text{CO}}_{\text{2}}$ is ${\text{CS}}_{\text{2}}$ .

Conclusion:

Hence, the possible compounds are ${\text{TeF}}_{\text{6}}$ , ${\text{NaSO}}_{\text{4}}$ , ${\text{BaCO}}_{\text{3}}$ and ${\text{CS}}_{\text{2}}$ .