Chapter 9, Problem 46QAP

(a)

Interpretation Introduction

Interpretation: The formula of a solid polar molecule containing oxygen should be determined.

Concept Introduction : The solid substances are classified as molecular and non-molecular in nature. The molecular solids can be polar and non-polar in nature. In a polar molecule, one side of molecule is negatively charged, whereas the other one is positively charged. When these opposite charged molecules come in contact, they exert a dipole-dipole interaction and hydrogen bonding to form a polar bond. Similarly, non-polar molecules do not have a separation between negative and positively charged sides. The solids containing these types of bonds are identified as polar and non-polar solids respectively.

Ionic bonds are formed between the atoms of two species having opposite charges. In such bonds, the excess electrons from one atom are donated to the adjoining atom in order to stabilize the molecule/compound. They are mostly formed between a metal and non-metal.

Network covalent or covalent bonds are formed when atoms of various species share the electrons in their outer orbital. It has very low polarity and the bonds are formed between species with almost similar electro-negativity.

Answer to Problem 46QAP

An example of polar molecular solid is nitrogen monoxide, $\text{NO}$ .

Explanation of Solution

Nitrogen monoxide ( $\text{NO}$ )

1. The number of valence electrons of both species.

Nitrogen (N) has 5 valence electrons and Oxygen (O) has six valence electrons.

2. The formation of double bond between N and O takes place by sharing of four electrons between them. And rest of the valence electrons are present as lone pair electrons
3. Using the Lewis dot structure of $\text{NO}$ will be:

  

Since, O is most electronegative than N so, it has tendency to attract the shared pair of electron towards them and possess the negative charge, whereas the N will possess positive charge.

This proves that the charges are unevenly distributed and hence, this molecule is polar in nature.

(b)

Interpretation Introduction

Interpretation: The formula of a solid ionic compound containing oxygen should be determined.

Concept Introduction : The solid substances are classified as molecular and non-molecular in nature. The molecular solids can be polar and non-polar in nature. In a polar molecule, one side of molecule is negatively charged, whereas the other one is positively charged. When these opposite charged molecules come in contact, they exert a dipole-dipole interaction and hydrogen bonding to form a polar bond. Similarly, non-polar molecules do not have a separation between negative and positively charged sides. The solids containing these types of bonds are identified as polar and non-polar solids respectively.

Ionic bonds are formed between the atoms of two species having opposite charges. In such bonds, the excess electrons from one atom are donated to the adjoining atom in order to stabilize the molecule/compound. They are mostly formed between a metal and non-metal.

Network covalent or covalent bonds are formed when atoms of various species share the electrons in their outer orbital. It has very low polarity and the bonds are formed between species with almost similar electro-negativity.

Answer to Problem 46QAP

An example of ionic solid is calcium oxide, $\text{CaO}$ .

Explanation of Solution

Calcium Oxide ( $\text{CaO}$ )

1. The first rule of an ionic bond is that it occurs between metal (Ca) and non-metal (O) by transfer of valence electrons.
2. Using the Lewis dot structure, calcium (Ca) has 2 valence electrons and oxygen (O) has 6 valence electrons. Using a single bond, Ca donates its 2 valence electrons to O and thus Ca gains (+2, positive ion) charge, whereas O get (-2, negative ion) charge. As they combine through opposite charges (complete transfer of electrons), an ionic bond is formed.

  

(c)

Interpretation Introduction

Interpretation: The formula of a solid network covalent molecule containing oxygen should be determined.

Concept Introduction : The solid substances are classified as molecular and non-molecular in nature. The molecular solids can be polar and non-polar in nature. In a polar molecule, one side of molecule is negatively charged, whereas the other one is positively charged. When these opposite charged molecules come in contact, they exert a dipole-dipole interaction and hydrogen bonding to form a polar bond. Similarly, non-polar molecules do not have a separation between negative and positively charged sides. The solids containing these types of bonds are identified as polar and non-polar solids respectively.

Ionic bonds are formed between the atoms of two species having opposite charges. In such bonds, the excess electrons from one atom are donated to the adjoining atom in order to stabilize the molecule/compound. They are mostly formed between a metal and non-metal.

Network covalent or covalent bonds are formed when atoms of various species share the electrons in their outer orbital. It has very low polarity and the bonds are formed between species with almost similar electro-negativity.

Answer to Problem 46QAP

An example of network covalent solid is quartz, ${\text{SiO}}_{\text{2}}$ .

Explanation of Solution

Quartz ( ${\text{SiO}}_{\text{2}}$ )

1. Silicon has four valence electrons and two atoms of oxygen gives a total of 12 valence electrons. The total number of valence electrons is thus (12+4= 16). So, either Silicon can take four electrons from Oxygen or Oxygen gains all the four electrons of Silicon thereby leaving it without any electrons.
2. From the Lewis structure, it is evident that the four electrons that Si requires are shared by the outer orbital of adjoining oxygen atoms. Thus covalent bonds are formed. Apart from the given form, SiO₂ can also exist like a grid containing repetitive units of Si and O such that its bond sharing continues through the substance.

  

(d)

Interpretation Introduction

Interpretation: The formula of a non-polar molecule containing oxygen should be determined.

Concept Introduction : The solid substances are classified as molecular and non-molecular in nature. The molecular solids can be polar and non-polar in nature. In a polar molecule, one side of molecule is negatively charged, whereas the other one is positively charged. When these opposite charged molecules come in contact, they exert a dipole-dipole interaction and hydrogen bonding to form a polar bond. Similarly, non-polar molecules do not have a separation between negative and positively charged sides. The solids containing these types of bonds are identified as polar and non-polar solids respectively.

Ionic bonds are formed between the atoms of two species having opposite charges. In such bonds, the excess electrons from one atom are donated to the adjoining atom in order to stabilize the molecule/compound. They are mostly formed between a metal and non-metal.

Network covalent or covalent bonds are formed when atoms of various species share the electrons in their outer orbital. It has very low polarity and the bonds are formed between species with almost similar electro-negativity.

Answer to Problem 46QAP

An example of the non-polar case is solid oxygen molecule, ${\text{O}}_{\text{2}}$ .

Explanation of Solution

Oxygen molecule ( ${\text{O}}_{\text{2}}$ )

1. The first rule on non-polar molecule is that it must have an even distribution of charge.
2. The number of valence electrons of oxygen is six. Using a double bond (where one bond refers to two electrons) both atoms can satisfy the octet rule and the molecule is uniformly charged. Hence, it is a non-polar molecule.
3. Although, oxygen is naturally in gaseous form, yet solid oxygen can form at a temperature below -219^oC.

Lewis dot structure of O₂ molecule: