Chapter 7, Problem 67A

Solution

(a)

Interpretation:

The ratio of cation to anion in potassium chloride needs to be determined.

Concept introduction:

Molecules are bound together by different types of bonds namely ionic and covalent. Ionic bonds are formed when there is complete transfer of electrons from one atom to another. These atoms either lose or gain electrons to become negatively or positively charged ions. In ionic compound, the number of cations is equal to the number of anions involved.

The ratio of cation to anion in potassium chloride is 1:1

Ionic bonds involve the transfer of electrons from one atom to the other. The metal atoms, an electrons donor, loses electrons to form a positively charged ion while the non-metal atoms, electron acceptor, gains electrons to form negatively charged ions. During the process of donating or gaining electrons, the atoms follow octet rule to attain a stable noble gas configuration. Therefore, the charges on the anion and cation depends on the electrons lost or gained giving net charge of zero.

Potassium has atomic number as 19 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^6{\text{3s}}^{2}3{\text{p}}^{6}4{\text{s}}^{\text{1}}$. Hence, it has 1 outermost electron which can be given up to form ${\text{K}}^{\text{+}}$.

Chlorine has atomic number as 17 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^6{\text{3s}}^{2}3{\text{p}}^5$. It has 7 valence electrons and needs only one electron to get octet configuration. It will gain one electron to form ${\text{Cl}}^{\text{-}}$.

The compound between Potassium and Chlorine is Potassium chloride in which the anion to cation ratio is 1:1.

(b)

Interpretation:

The ratio of cation to anion in calcium fluoride needs to be determined.

Concept introduction:

Molecules are bound together by different types of bonds namely ionic and covalent. Ionic bonds are formed when there is complete transfer of electrons from one atom to another. These atoms either lose or gain electrons to become negatively or positively charged ions. In ionic compound, the number of cations is equal to the number of anions involved.

The ratio of cation to anion in calcium fluoride is 1:2

Ionic bonds involve the transfer of electrons from one atom to the other. The metal atoms, an electrons donor, loses electrons to form a positively charged ion while the non-metal atoms, electron acceptor, gains electrons to form negatively charged ions. During the process of donating or gaining electrons, the atoms follow octet rule to attain a stable noble gas configuration. Therefore, the charges on the anion and cation depends on the electrons lost or gained giving net charge of zero.

Calcium has atomic number as 20 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^6{\text{3s}}^{2}3{\text{p}}^{6}4{\text{s}}^2$. Hence, it has 2 outermost electron which can be given up to form ${\text{Ca}}^{\text{2+}}$.

Fluorine has atomic number as 9 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^5$. It has 7 valence electrons and needs only one electron to get octet configuration. It will gain one electron to form ${\text{F}}^{\text{-}}$.

The compound between Calcium and Fluorine is Calcium fluoride wherein the cation is ${\text{Ca}}^{\text{2+}}$ and anion is ${\text{F}}^{\text{-}}$. Here, the anion to cation ratio is 1:2.

(c)

Interpretation:

The ratio of cation to anion in calcium oxide needs to be determined.

Concept introduction:

Molecules are bound together by different types of bonds namely ionic and covalent. Ionic bonds are formed when there is complete transfer of electrons from one atom to another. These atoms either lose or gain electrons to become negatively or positively charged ions. In ionic compound, the number of cations is equal to the number of anions involved.

The ratio of cation to anion in calcium oxide is 1:1

Ionic bonds involve the transfer of electrons from one atom to the other. The metal atoms, an electrons donor, loses electrons to form a positively charged ion while the non-metal atoms, electron acceptor, gains electrons to form negatively charged ions. During the process of donating or gaining electrons, the atoms follow octet rule to attain a stable noble gas configuration. Therefore, the charges on the anion and cation depends on the electrons lost or gained giving net charge of zero.

Calcium has atomic number as 20 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^6{\text{3s}}^{2}3{\text{p}}^{6}4{\text{s}}^2$. Hence, it has 2 outermost electron which can be given up to form ${\text{Ca}}^{\text{2+}}$.

Oxygen has atomic number as 8 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^4$. It has 6 valence electrons and needs two electrons to get octet configuration. It will gain two electrons to form ${\text{O}}^{\text{2-}}$.

The compound between Calcium and oxygen is Calcium oxide in which the anion is ${\text{O}}^{\text{2-}}$ and cation is ${\text{Ca}}^{\text{2+}}$. The cation to anion ratio is 1:1.

(d)

Interpretation:

The ratio of cation to anion in Strontium chloride needs to be determined.

Concept introduction:

Molecules are bound together by different types of bonds namely ionic and covalent. Ionic bonds are formed when there is complete transfer of electrons from one atom to another. These atoms either lose or gain electrons to become negatively or positively charged ions. In ionic compound, the number of cations is equal to the number of anions involved.

The ratio of cation to anion in Strontium chloride is 1:2

Ionic bonds involve the transfer of electrons from one atom to the other. The metal atoms, an electrons donor, loses electrons to form a positively charged ion while the non-metal atoms, electron acceptor, gains electrons to form negatively charged ions. During the process of donating or gaining electrons, the atoms follow octet rule to attain a stable noble gas configuration. Therefore, the charges on the anion and cation depends on the electrons lost or gained giving net charge of zero.

Strontium has atomic number as 38 with electronic configuration as $\left[\text{Kr}\right]5{\text{s}}^{\text{2}}$. Hence, it has 2 outermost electron which can be given up to form ${\text{Sr}}^{\text{2+}}$.

Chlorine has atomic number as 17 with electronic configuration as ${\text{1s}}^2{\text{2s}}^2{\text{2p}}^6{\text{3s}}^{2}3{\text{p}}^5$. It has 7 valence electrons and needs only one electron to get octet configuration. It will gain one electron to form ${\text{Cl}}^{\text{-}}$.

The compound between Strontium and Chlorine is Strontium chloride in which the anion is ${\text{Cl}}^{\text{-}}$ to cation is ${\text{Sr}}^{\text{2+}}$. The ratio of anion to cation is 1:2.