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CHM 101

INTRODUCTORY INORGANIC CHEMISRTY

Course Team Professor John Kanayochukwu Nduka (Course Reviewer) – NAU Awka

NATIONAL OPEN UNIVERSITY OF NIGERIA

COURSE

GUIDE

CHM 101 COURSE GUIDE iii

CONTENTS PAGE

Introduction …………………………………….. iv What you will learn in this course………………. iv Course Aims……………………………………... iv Course Objectives……………………………….. v Working through this course…………………….. v Course Materials ………………………………... v Study Units……………………………………… v Textbooks……………………………………….. vii Assessment……………………………………… vii Summary………………………………………... vii

CHM 101 COURSE GUIDE iv

INTRODUCTION

Inorganic Chemistry is the study of chemical elements and their compounds excluding compounds of carbon; but compounds of carbon and oxygen, Sulphur and metals are generally included in inorganic chemistry. An element is a substance which cannot be resolved into two or more simpler substances following any known chemical process. Combination 0f two or more elements chemically form a new substance called compounds. Examples, water (formed from hydrogen and oxygen), common salt (formed from sodium and chlorine), carbon dioxide (from carbon and oxygen). Since scientist systematize the knowledge gained through observation and experiments. Development of periodic table and periodic law is an example of such attempt that has brought order in studying an expansive branch of chemistry covering over a hundred element. It is therefore pertinent to start the study of inorganic chemistry with the focus on the periodic table. CHM 101 – Introductory inorganic chemistry is a two (2) credit hour course of seventeen (17) units. The course is designed to equip the student with in- depth knowledge of the periodic classification of element, properties of element according to groups and periods. The course is designed to deal with periodic table and periodic law, electronic configuration, atomic radii, ionization energy, affinity of electrons, electronegativity, hydrogen, its reaction and compounds, Alkali and Alkaline earth metals compounds, physical and chemical properties etc. This course guide gives the student a brief overview of the course content, course duration, and course materials.

WHAT YOU WILL LEARN IN THIS COURSE

The student will learn about the periodic table, how it came to be, and the periodic law. Scientist that contributed to the development of periodic table. Hydrogen, chemical properties and reactions. Alkali and Alkaline earth metals, their physical and chemical properties. Reactions and uses.

COURSE AIMS

The aim of this course is tailored towards teaching the students to understand periodic classification of elements, various contributors to the development of periodic table. Modern periodic law, electronic configuration and rules governing its atomic radii, ionization energy, affinity of electrons, electronegativity, Hydrogen, its properties, its bonding, manufacture, ionic

CHM 101 COURSE GUIDE vi

STUDY UNITS

The following are the three modules and the seventeen units contained in this course. Module 1 Unit 1 Periodic Table Unit 2 Modern Periodic Law Unit 3 Electronic Configuration Unit 4 Atomic Radius Unit 5 Ionization Energy Unit 6 Electron Affinity Unit 7 Electronegativity Module 2 Unit 1 Hydrogen Unit 2 Manufacture of Hydrogen Unit 3 Ion and Salt-like Hydride Unit 4 Hydrogen Bonding Module 3 Unit 1 General Physical and Chemical Characteristics of the Alkaline Metals Unit 2 Compounds of Alkali Metals Unit 3 Solvation of Alkaline Metal Ions Unit 4 Alkaline Earth Metals Unit 5 Reactivity of Alkaline Earth Metals Unit 6 Complexing Behaviour of Alkaline Earth Metals In module 1, introduction to periodic classification, attempt and contribution of J.W Dobereiner, Ade Chancourtois, John Newlands etc. Unit 2 discussed modern periodic law and nomenclature of elements having Z > 100; Unit 3 deals with the rules of filling orbitals, configuration of elements, ion and division of elements into blocks. Atomic radii, covalent radius, periodicity, periodicity in ionization energy etc. were discussed in unit 4 and 5 while unit 6 and 7 discussed factors affecting electron affinity, Pauling electronegativity, Maulliken-Jafffe electronegativity and Alfred Rochow electronegativity.

CHM 101 COURSE GUIDE vii Module 2 contains units 8, 9, 10 and 11 and contains extensive discussion of hydrogen, its position in the periodic table, its isotopes, manufacture, properties, uses, ionic or salt-like hydrides and metallic hydride, Hydrogen bonding, its effect on boiling and melting point, water solubility and polarizing power of hydrogen ion. Unit 12 of module 3 took a look at the general physical and chemical properties of alkali and alkaline earth metal, their uses. Unit 13 discussed the compounds of alkali metals, oxides of hydrogen. Unit 14 explained solvation of alkaline metal ions, their complexation behavior and anomalous nature of lithium. Unit 15 and 16 dwelt on alkaline earth metals and their properties reactivity, occurrence, extraction, lattice energy, hydration energy and thermal stability of oxysalts. The course ends with unit 17 of module 3 by explaining complexation behaviour of alkaline earth metals and anomalous nature of Beryllium.

TEXTBOOKS AND REFERENCES

There are several books and other materials that treated Inorganic Chemistry

101. A good number of them are written down in the references. The internet provides a lot of useful information concerning the course, therefore, the student is encouraged to use the internet and NOUN e-library were possible.

ASSESSMENT

There are two aspects of assessment for this course; the tutor-marked assignment (TMA) and end of course examination. TMAs shall constitute the continuous assessment component of the course. They will be marked by the tutor and shall account for 30% of the total course score. Each learner shall be examined for four TMAs before the end of course examination. The end of course examination shall constitute 70% of the total course score.

SUMMARY

This course is necessary as an introductory Inorganic Chemistry course. It opens up and introduces the student into the wider knowledge of the Chemistry of all the elements as classified in the periodic table, the historical development of the periodic table, the special place of Mendeleev in the development of modern periodic table and periodic law. Chemical and

CONTENTS PAGE

MAIN

• Module 1……………………………………………………
• Unit 1 Periodic Table ……………………………….
• Unit 2 Modern Periodic Law………………………...
• Unit 3 Electronic Configuration……………………..
• Unit 4 Atomic Radius………………………………..
• Unit 5 Ionization Energy……………………………..
• Unit 6 Electron Affinity………………………………
• Unit 7 Electronegativity………………………………
• Module 2…………………………………………………….
• Unit 1 Hydrogen …………………………………….
• Unit 2 Manufacture of Hydrogen……………………
• Unit 3 Ion and Salt-like Hydride…………………….
• Unit 4 Hydrogen Bonding……………………………
• Module 3…………………………………………………….
  • of the Alkaline Metals………………………… Unit 1 General Physical and Chemical Characteristics
• Unit 2 Compounds of Alkali Metals………………….
• Unit 3 Solvation of Alkaline Metal Ions……………..
• Unit 4 Alkaline Earth Metals…………………………
• Unit 5 Reactivity of Alkaline Earth Metals…………..
  • Metals………………………………………… Unit 6 Complexing Behaviour of Alkaline Earth

CHM 101 MODULE 1 1

MODULE 1

Unit 1 Periodic Table Unit 2 Modern Periodic Law Unit 3 Electronic Configuration Unit 4 Atomic Radius Unit 5 Ionization Energy Unit 6 Electron Affinity Unit 7 Electronegativity

UNIT 1 THE PERIODIC TABLE

1 .0 Introduction 2.0 Intended Learning Outcomes (ILOs) 3.0 Main content 3.1 Beginning of Classification 3.2 Attempt made by J.W Dobereiner 3.3 Attempt made by Ade Chancourtois 3.4 Attempt made by John Newlands 3 .5 The work of Lothar Meyer 3.6 Mendeleevs Periodic law 4.0 Conclusion 5.0 Summary 6.0 Tutor Mark Assignment 7.0 References/Further Readings

1.0 INTRODUCTION

You are aware that scientists, from the very beginning have attempted to systematize the knowledge they gain through their observations and experiments.. Development of the periodic law and the periodic table of the elements is one of such attempt. This has brought order in the study of the vast chemistry of more than a hundred elements known now. It is therefore quite natural that you should begin your study of inorganic chemistry with the study of the periodic table. In this unit, you will be starting from the very beginning, that is, with the very first attempt made at classification of the elements. As early as 1815 Prout advanced the hypothesis that all elements were formed by the coalescence of hydrogen atoms, on inaccurate evidence that all atomic masses were whole numbers but it was Berzelius who showed that ‘atomic mass’ of chlorine was not 35 nor 36 but 35.5 far from a whole number. The discovery of isotope proved that chlorine was a mixture of containing two different kinds of atoms of mass 35 and 37.

CHM 101 MODULE 1 3 In contrast to metallic elements, non-metallic elements have no characteristic appearance. They are brittle that is they break easily. They are poor conductors of electricity and heat. They form acidic oxides. As more elements were discovered and knowledge of physical and chemical properties were refined, it became clear that within these two divisions of elements, there existed families of elements whose properties varied systematically from each other. Furthermore, certain elements, the metalloids possessed properties intermediate between the two divisions. Thereore were made to search for other classifications.

3.2 Attempts Made by J W Dobereiner

In 1829 J W Dobereiner observed that there exist certain groups of three elements which the called TRIADS. He also observed that elements in triad not only had similar properties, but also the atomic weight of the middle element was approximately an average of the atomic weights of the other two elements of the triad. A few examples cited by him were: Li, Na, K, Ca, Sr, Ba, S, Se, Te and Cl. Br, I, Al though, Doberieiner's relationship seems to work only fora few elements, He was the first to point out a systematic relationship among the elements. This was followed by Cannizzaro’s unambiguous atomic mass with the consequent allotment of valencies to atoms as a measure of combining power. In-text Question State Prout’s (1815) hypothesis of the elements explain how the error was corrected.

3.3 Attempts Made by A. Dechancourtois

In 1862, A. DeChanourtois arranged the elements that were known at that time in order of increasing atomic weight on a line which spiralled around a cylinder from bottom to top.

3.4 Attempts Made by John Newlands

In 1864, John Newlands, an English Chemist reported his "LAW OF OCTAVES" He suggested that if the elements were arranged in order of increasing atomic weight, every eighth element would have properties similar to the first element. It brought the lithium-sodium- potassium triad together but failed to allow bigger octave if dealing with

CHM 101 INTRODUCTION INORGANIC CHEMISTRY 4 heavier elements. For example, He arranged the elements in the following manner. Table 1: John Newland’s arrangement of the element Element Li Be B c N 0 F AtWt 7 9 11 12 14 16 19 Element Na Mg Al Si P S Cl AtWt 23 24 27 29 31 32 35. Element K Ca Ti Cr AtWt 39 40 48 32 Thus we see K resembles Na and Li, Ca resembles Mg and Be, Al resembles B, Si resembles C and so on. He called it the "Law of octaves" because he says the cycle of repetition shown by the elements is like that shown by octaves of music where every eight note resembles the first in octaves of music. Newlands "Law of octaves" was rejected for two reasons. Firstly, it did not hold good for elements heavier than Ca. Secondly, he believed that there existed some mystical connection between music and chemistry.

3.5 The Work of Lothar Meyer

Lothar Meyer and Dmitri Mendeleev whom you will read about next played key role in the development of the periodic law as it is known today. In 1869, Lothar Meyer reported that when physical properties like atomic volume, boiling point etc. were plotted against atomic weight, a periodically repeating curve was obtained in each case. Figure 1 is a graph showing the variation in atomic volume with atomic number. Lothar Meyer calculated the atomic volumes of the known elements, that is the volume in cm^3 occupied by 1mole of the elements in the solid state Atomic volume = Mass of one Mol ̷Density (Lothar Meyer also obtained semi curve by plotting atomic volume versus atomic weight) The atomic volume behaviour is p e r i o d i c. It goes through circles, dropping from a sharp maximum to a minimum and then sharply rising again. Each of the cycles is called a period. The location of element on the peak or in the troughs has an important correlation with their chemical

CHM 101 INTRODUCTION INORGANIC CHEMISTRY 6 Table 2. Mendeleev periodic table of against each element is the value of atomic weight Ser ies Gro up I Gro up II Grou p III Grou p IV Gro up V Grou p VI Grou p VII Group VIII

• • • RH 4 RH 3 RH 2 RH - R 1 O RO R 2 O 3 RO 2

R 2 O

6

IO 2 R 1 O 1 RO 4

1 H=

Li= 7 Bc=

B=

C=

N=

O=

6 F=

Na= 23 Mg = Al=

Si= 8

P=

1 S=

Cl=

4

K=

Ca= 40 Sc= 4 Ti= 8

V=

Cr= 2 Mn= 55 Fe=56, Co= Ni= 5 Cu= 63 Zn= 65 Ga= 68 Ge= 72 As= 75 Sc= 8 Bi= 0 6 Rb= 85 Sr= 87 Yt= 8 Zr= 0 Nb= 94 Mo= 96 Fm= 100 Ru=104, Rh= Pd=106, 7 Ag= 108 Cd= 112 In= 13 Sn= 18 Sb= 122 Te= 25

I=

Cs= 133 Ba= 137 Da= 138 Ce= 148 - - -

Er= 78 La= 80 Ta= 182

W=

Os=195, Ls=195, Pi= 11 Au= 199 Hg= 200 Ti= 04 Pb= 07 Bi= 208 12 - - Th= 231 -

U=

Though Newlands and Lothar Meyer also contributed in developing the periodic laws, the main credit goes to Mendeleev because of the following reasons: a. He included along with his table, a detailed analysis of the properties of all known elements and correlated a broad range of physical and chemical properties with atomic weights.

CHM 101 MODULE 1 7 b. He kept his primary goal of arranging similar elements in the same group quite clear. Therefore, he was bold enough in reversing the order of certaine elements. For example, iodine with lower atomic weight than that of tellurium (group VI) was placed in group VII along with fluorine, chlorine and bromine because of similarities in properties. c. He also corrected the atomic weight of certain elements to include the min proper groups. For example, he corrected the atomic weight of beryllium (from 13.5 to 9) and indium (from 76 to 114) without doing any actual measurement. His competence was proved correct as Be and La with equivalent weight of 4.5 and 38 respectively are actually bivalent and trivalent. d. Keeping to his primary goal of arranging similar elements in the same vertical column (group), he realized that some of the elements were still undiscovered and therefore left their places vacant in the table and predicted their properties. He predicted the existence in nature of over ten new elements and predicted properties of three of them, example eka-boron (scandium), eka aluminium (gallium) and eka silicon (germanium) from the properties of known elements surrounding them. When these elements were eventually discovered, Mendeleev prediction proved to be amazingly accurate. This you can see for yourself by comparing the prediction and observed properties of eka- alurninium (gallium) and eka silicon (germanium) given in table

2. The validity of Mendeleev periodic law was dramatically and conclusively proven by the discovery of three out of the more than ten elements predicted by Mendeleev. The first to be discovered was eka-aluminiurn which was discovered by Lecoq de Boisbaudran in 1875.

CHM 101 MODULE 1 9 The development of the periodic law is an excellent example where careful observation, critic analys of available data without any pre- conceived notions and scientific foresight led to the discovery of a fundamental law of nature. Thus when Mendeleev arranged elements in order of increasing atomic weights, he critically analyzed the properties of the then known elements. He discovered that the properties of any element are an average of the properties of its neighbours in the periodic table. On this basis, he predicted the properties of undiscovered elements representing the gaps in the table. The many gaps in the table which Mendeleeff correctly predicted would eventually be filled by the discovery of more elements. No gaps remain to be filled, therefore the properties of many of these element are in close agreement with those predicted by Mendeleeff. In modern periodic table, the ordering of the element is based on atomic numbers rather than atomic masses. This accommodated the discovery of the noble gasses, 14 rare earths (the first inner transition series called the lanthanides) and 11 man-made elements (part of the second inner transition series called the actinides) In-text Question Question State the point that makes Mendeleev’s periodic law stronger than Lother Meyer’s SELF-ASSESSMENT EXERCISES i. Give the names of the scientist whose work contributed to the development of the periodic table? ii. The law of octave was developed by_____

4.0 CONCLUSION

In conclusion, the Scientists tradition of recording and system knowledge gained through observations and experiments has enabled us to learn about the fundamental laws governing the arrangement of elements. Mendeleev prediction proved to be amazingly accurate. This you can see for yourself by comparing the prediction and observed properties of eka- alurninium (gallium) and eka silicon (germanium).

5.0 SUMMARY

In summary, we have learned the following in this unit, these are:

1. Scientists have always tried to systemize the knowledge they gain.

CHM 101 INTRODUCTION INORGANIC CHEMISTRY 10

2. That the effort to reveal the secrets of the periodic table were led by the scientist J W Dobreiner, A de chanourtois, John Newlands, Lothar Meyer and Dmitir Mendeleev.
3. That the works of Dmitir Mendeleev formed the basis of the modern Periodic law.
4. That according to Mendeleev, the properties o f any element a r e an average of the properties of its neighbours in the periodic table. 6.0 TUTOR MARK ASSSIGNMENT
5. (a) What property did Mendeleev use to classify the element in his periodic table? (b) Enumerate four defects in the Mendeleev's periodic table
6. Assuming that the element Ca had not been discovered, predict using the properties of the Known element surrounding Ca its own properties such as its atomic weight and density.

7.0 REFERENCES/ FURTHER READING

J. G Wilson, A. B. Newell (1971) General and Inorganic Chemistry (2nd edition) Published by Cambridge University Pres F. A Cotton, G. Wilkinson and P. L. Gayus (1995) Basic Inorganic Chemistry. (3nd^ edition) John Wiley and Sons Published Gary L. Miessler, Paul J. Fischer and Donald A. Tour (2014) Inorganic Chemistry. 5th edition. Pearson Publishers. ISBN 10:0- 321 - 81105 - 4 J. D Lee (2016) Concise Inorganic Chemistry. (5th^ edition) John Wiley Publishers