This document discusses the electronic configuration of carbon and how it forms bonds. It explains that carbon normally forms four single bonds by undergoing sp3 hybridization, where one 2s orbital and three 2p orbitals combine to form four new hybrid orbitals oriented toward the corners of a tetrahedron. It also discusses sp2 and sp hybridization which allow carbon to form multiple and triple bonds. The document contrasts primary covalent, ionic, and coordinate covalent bonds from secondary bonds formed by hydrogen bonding and van der Waals forces.
CONTENTS
INTRODUCTION
CONCEPTS OF WALSH DIAGRAM
APPLICATION IN TRIATOMIC MOLECULES
[IN AH₂ TYPE OF MOLECULES(BeH₂,BH₂,H₂O)]
INTRODUCTION
Arthur Donald Walsh FRS The introducer of walsh diagram (8 August 1916-23 April 1977) was a British chemist, professor of chemistry at the University of Dundee . He was elected FRS in 1964. He was educated at Loughborough Grammar School.
Walsh diagrams were first introduced in a series of ten papers in one issue of the Journal of the Chemical Society . Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by applying theoretical contributions made by Mulliken .
A ppt compiled by Yaseen Aziz Wani pursuing M.Sc Chemistry at University of Kashmir, J&K, India and Naveed Bashir Dar, a student of electrical engg. at NIT Srinagar.
Warm regards to Munnazir Bashir also for providing us with refreshing tea while we were compiling ppt.
Molecular orbital theory (MOT) is an alternative model to valence bond theory that explains how atomic orbitals from different atoms combine to form molecular orbitals. The linear combination of atomic orbitals (LCAO) method considers the probability of finding electrons in atomic orbitals from different atoms. According to the LCAO method, molecular orbitals are formed from constructive and destructive interference of atomic orbitals. MOT can be used to explain bonding in homonuclear diatomic molecules like N2 and O2, heteronuclear diatomic molecules like CO and NO, and polyatomic molecules like CO2 and SF6. It can also describe bonding in octahedral transition metal complexes like hexaaquoferrate(II) ion
The document discusses nuclear magnetic resonance (NMR) spectroscopy, specifically proton (1H) and carbon-13 (13C) NMR. It provides information on why NMR is used, the types of information it can provide about compounds, and the physical properties of 1H and 13C nuclei that influence their NMR spectra. It also discusses factors that affect chemical shifts, common chemical shift ranges, coupling behaviors, and how to determine the number of signals expected for given compounds from their carbon environments. The document aims to explain the fundamentals and applications of 1H and 13C NMR spectroscopy.
Charge-Transfer-Spectra. metal to metal, metal to ligandNafeesAli12
The document discusses charge transfer spectra in metal complexes. There are four main types of charge transfer transitions: ligand to metal (LMCT), metal to ligand (MLCT), intermetal or metal to metal (MMCT), and interligand (LLCT). LMCT involves electron transfer from ligand orbitals to metal orbitals, while MLCT is the reverse with electron transfer from metal to ligand orbitals. MMCT occurs between different oxidation states of the same metal. LLCT takes place between different ligands, one acting as an electron donor and the other as an acceptor. Examples are provided of each type of charge transfer and how they influence the color of complexes.
CONTENTS
INTRODUCTION
CONCEPTS OF WALSH DIAGRAM
APPLICATION IN TRIATOMIC MOLECULES
[IN AH₂ TYPE OF MOLECULES(BeH₂,BH₂,H₂O)]
INTRODUCTION
Arthur Donald Walsh FRS The introducer of walsh diagram (8 August 1916-23 April 1977) was a British chemist, professor of chemistry at the University of Dundee . He was elected FRS in 1964. He was educated at Loughborough Grammar School.
Walsh diagrams were first introduced in a series of ten papers in one issue of the Journal of the Chemical Society . Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by applying theoretical contributions made by Mulliken .
Bonding and Antibonding interactions; Idea about σ, σ*, π, π *, n – MOs; HOMO, LUMO and SOMO; Energy levels of π MOs of different conjugated acyclic and cyclic systems; Hückel’s rules for aromaticity; Frost diagram
CONTENTS
INTRODUCTION
CONCEPTS OF WALSH DIAGRAM
APPLICATION IN TRIATOMIC MOLECULES
[IN AH₂ TYPE OF MOLECULES(BeH₂,BH₂,H₂O)]
INTRODUCTION
Arthur Donald Walsh FRS The introducer of walsh diagram (8 August 1916-23 April 1977) was a British chemist, professor of chemistry at the University of Dundee . He was elected FRS in 1964. He was educated at Loughborough Grammar School.
Walsh diagrams were first introduced in a series of ten papers in one issue of the Journal of the Chemical Society . Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by applying theoretical contributions made by Mulliken .
A ppt compiled by Yaseen Aziz Wani pursuing M.Sc Chemistry at University of Kashmir, J&K, India and Naveed Bashir Dar, a student of electrical engg. at NIT Srinagar.
Warm regards to Munnazir Bashir also for providing us with refreshing tea while we were compiling ppt.
Molecular orbital theory (MOT) is an alternative model to valence bond theory that explains how atomic orbitals from different atoms combine to form molecular orbitals. The linear combination of atomic orbitals (LCAO) method considers the probability of finding electrons in atomic orbitals from different atoms. According to the LCAO method, molecular orbitals are formed from constructive and destructive interference of atomic orbitals. MOT can be used to explain bonding in homonuclear diatomic molecules like N2 and O2, heteronuclear diatomic molecules like CO and NO, and polyatomic molecules like CO2 and SF6. It can also describe bonding in octahedral transition metal complexes like hexaaquoferrate(II) ion
The document discusses nuclear magnetic resonance (NMR) spectroscopy, specifically proton (1H) and carbon-13 (13C) NMR. It provides information on why NMR is used, the types of information it can provide about compounds, and the physical properties of 1H and 13C nuclei that influence their NMR spectra. It also discusses factors that affect chemical shifts, common chemical shift ranges, coupling behaviors, and how to determine the number of signals expected for given compounds from their carbon environments. The document aims to explain the fundamentals and applications of 1H and 13C NMR spectroscopy.
Charge-Transfer-Spectra. metal to metal, metal to ligandNafeesAli12
The document discusses charge transfer spectra in metal complexes. There are four main types of charge transfer transitions: ligand to metal (LMCT), metal to ligand (MLCT), intermetal or metal to metal (MMCT), and interligand (LLCT). LMCT involves electron transfer from ligand orbitals to metal orbitals, while MLCT is the reverse with electron transfer from metal to ligand orbitals. MMCT occurs between different oxidation states of the same metal. LLCT takes place between different ligands, one acting as an electron donor and the other as an acceptor. Examples are provided of each type of charge transfer and how they influence the color of complexes.
CONTENTS
INTRODUCTION
CONCEPTS OF WALSH DIAGRAM
APPLICATION IN TRIATOMIC MOLECULES
[IN AH₂ TYPE OF MOLECULES(BeH₂,BH₂,H₂O)]
INTRODUCTION
Arthur Donald Walsh FRS The introducer of walsh diagram (8 August 1916-23 April 1977) was a British chemist, professor of chemistry at the University of Dundee . He was elected FRS in 1964. He was educated at Loughborough Grammar School.
Walsh diagrams were first introduced in a series of ten papers in one issue of the Journal of the Chemical Society . Here, he aimed to rationalize the shapes adopted by polyatomic molecules in the ground state as well as in excited states, by applying theoretical contributions made by Mulliken .
Bonding and Antibonding interactions; Idea about σ, σ*, π, π *, n – MOs; HOMO, LUMO and SOMO; Energy levels of π MOs of different conjugated acyclic and cyclic systems; Hückel’s rules for aromaticity; Frost diagram
Pyrolytic elimination reactions involve the application of heat to induce an elimination reaction in an organic substrate without the need for an external base or solvent. This type of elimination proceeds through a concerted, syn-elimination via a cyclic transition state that allows for an intramolecular proton transfer and the formation of a new carbon-carbon double bond. Specific examples of pyrolytic eliminations discussed in the document include the conversion of esters to carboxylic acids and alkenes, eliminations in alicyclic systems, Cope eliminations, sulfoxide eliminations, xanthate pyrolysis, and selenoxide eliminations.
This document summarizes a seminar presentation on dπ-pπ bonds. It introduces that d-orbitals on third period elements can participate in bonding. The eg orbitals can form σ-bonds by overlapping with s and p orbitals, while the t2g orbitals can combine with p orbitals of the same character. However, free atom d-orbital energies are high, the orbitals are diffuse rather than compact, and promotion energies to d-orbital states are around 30-35 eV, making significant d-orbital contributions to bonding unlikely except in certain cases.
Dynamic Stereochemistry and What role does conformation plays on stereochemistry is being exemplified in this presentation. Useful for the Undergraduate and Postgraduates students of Pharmacy, Pharmaceutical Chemistry and Chemical Sciences
Crystal field theory and ligand field theory describe how ligands interact with transition metal complexes. Crystal field theory uses an electrostatic model to explain orbital splitting, while ligand field theory uses a molecular orbital approach. Both theories predict that ligands cause the d orbitals on the metal to split into lower energy t2g and higher energy eg sets. The size of this splitting depends on whether ligands are σ-donors only, π-donors, or π-acceptors. π-Acceptors increase splitting while π-donors decrease it. This explains the spectrochemical series from weak to strong field ligands.
Kinetics of Pyrolysis of acetaldehyde PRUTHVIRAJ K
Jeevankumar M presented a seminar on the pyrolysis of acetaldehyde under the guidance of Mr. Pruthviraj. Pyrolysis is the thermal degradation of compounds in the absence of oxygen above the boiling point of water. The pyrolysis of acetaldehyde occurs through a chain reaction, producing methyl radicals and hydrogen. The mechanism involves initiation, propagation, and termination steps. Applying steady-state approximations, the rate law for the pyrolysis of acetaldehyde was determined to be third order with respect to acetaldehyde concentration. Pyrolysis has applications in producing fuels from waste and in industrial processes like steelmaking and syngas production.
Molecular orbital theory(mot) of SF6/CO2/I3-/B2H6sirakash
1) Molecular orbital theory views a molecule as delocalized molecular orbitals formed from linear combinations of atomic orbitals. Bonding molecular orbitals are lower in energy due to constructive interference, while antibonding orbitals are higher in energy due to destructive interference.
2) The document provides examples of applying molecular orbital theory to SF6, CO2, B2H6, and I3- molecules. It describes the atomic orbitals and molecular orbitals formed, including bonding, antibonding, and non-bonding orbitals, and explains how the molecular orbitals rationalize the electronic structures and bonding patterns in these molecules.
APPLICATIONS OF ESR SPECTROSCOPY TO METAL COMPLEXESSANTHANAM V
This document discusses the applications of electron spin resonance (ESR) spectroscopy to study metal complexes. It outlines several key factors that influence the ESR spectra of metal complexes, including the nature of the metal ion, ligands, geometry, number of d electrons, and crystal field effects. It also describes how zero-field splitting and Jahn-Teller distortions can lead to splitting of electronic levels and influence the number and pattern of transitions observed in ESR spectra. Understanding these various effects is important for extracting information about electronic structure and bonding from ESR data of metal complexes.
The Lindemann theory provides an explanation for unimolecular gas-phase reactions. It proposes that:
1) A molecule A acquires sufficient vibrational energy from collisions with other A molecules to form an energized molecule A*.
2) A* can then either lose its energy and revert to A, or it can decompose or isomerize in a subsequent reaction.
3) This process leads to first-order kinetics for the overall reaction rate, consistent with experimental observations of unimolecular reactions.
However, the Lindemann theory has some limitations, as the predicted rate constant versus concentration relationship is hyperbolic rather than linear as observed experimentally. More advanced theories like RRK and Slater were developed to
Metal nitrosyl compounds contain nitric oxide bonded as an NO+ ion, NO- ion, or neutral NO molecule. They can be classified into three classes based on the nitric oxide group present. Metal nitrosyls are coordination compounds where an NO molecule is attached as an NO+ ion to a metal atom or ion. Examples include metal nitrosyl carbonyls such as Co(NO+)(CO)3, metal nitrosyl halides such as Fe(NO+)2I, and metal nitrosyl thio-complexes involving Fe, Co, and Ni metals. These compounds can be prepared through the reaction of nitric oxide with metal compounds like carbonyls, halides, or ferrocyanides. Metal
Electrophilic aromatic substitution is a reaction where an atom attached to an aromatic system is replaced by an electrophile. The aromatic ring attacks the electrophile, forming a carbocation intermediate. This intermediate is stabilized by resonance. A Lewis base then donates electrons back to the ring, restoring aromaticity. Substituents can activate or deactivate the ring by donating or withdrawing electron density. Activating groups make the reaction more likely and direct substitution to the ortho- and para- positions, while deactivating groups have the opposite effects.
The document discusses molecular orbital theory and its application to transition metal complexes. It describes how atomic orbitals of matching symmetry combine to form molecular orbitals, with equal numbers of bonding and antibonding orbitals. Electrons fill the molecular orbitals starting with the lowest energy orbitals. Ligand interactions such as π-accepting and π-donating affect the splitting of orbitals and influence the metal's oxidation state.
The document discusses NMR spectroscopy of various nuclei and their applications to inorganic molecules. It provides details on the natural abundance, spin, magnetic moment, and magnetogyric ratio of common NMR-active nuclei such as 1H, 2H, 11B, 13C, 17O, 19F, 29Si, and 31P. It then discusses the applications of 19F, 29Si, and 31P NMR spectroscopy for structure elucidation of inorganic molecules. Examples are provided to illustrate how NMR chemical shifts and coupling constants can provide information about functional groups, molecular structures, and stereochemistry.
This document discusses electronic spectra of metal complexes. It begins by defining quantum numbers related to electron configuration, such as L (total orbital angular momentum) and l (secondary quantum number). It then describes two main types of electronic transitions in coordination compounds: d-d transitions specific to metals, and charge-transfer transitions. The remainder of the document discusses charge-transfer transitions in more detail, defining ligand-to-metal and metal-to-ligand charge transfer, and how solvent polarity affects these transitions.
The document discusses various types of aliphatic nucleophilic substitution reactions and their mechanisms. It covers SN2 and SN1 mechanisms in detail, providing evidence that supports each. It also discusses borderline cases where reactions have characteristics of both SN1 and SN2, and other mechanisms like SN1', SNi, SET, and addition-elimination that may occur under different conditions. Specific examples of nucleophilic substitution are discussed at allylic, trigonal, and vinylic carbons that may proceed by different pathways than typical SN1 or SN2 reactions.
Acid Base Hydrolysis in Octahedral ComplexesSPCGC AJMER
This document discusses acid and base hydrolysis in octahedral complexes. It covers factors that affect the rate of acid hydrolysis, including the charge on the complex, steric hindrance effects, and the strength of the leaving group. A higher positive charge, more steric hindrance, or stronger metal-leaving group bond each decrease the rate of acid hydrolysis according to first-order kinetics through a dissociative SN1 mechanism. Base hydrolysis of octahedral complexes can proceed by either associative SN2 or dissociative SN1 pathways depending on conditions.
This document presents information on the Tanabe-Sugano diagram, which is used in coordination chemistry to predict absorptions in the UV-visible and IR spectra of coordination compounds. It was developed by Yukito Tanabe and Satoru Sugano in 1954 to explain the absorption spectra of octahedral complex ions. The diagram plots orbital energy as a function of the Racah parameter B versus the ligand field splitting parameter Δo/B. It can be used to determine the ordering of electronic states and predict possible electronic transitions based on parameters like Δo, Racah parameters B and C, symmetry rules, and term symbols of electronic configurations. The diagram has advantages over earlier Orgel diagrams in that it can be applied to
Organic Reaction Mechanism : This topic is very-very important for CSIR-NET, GATE, IIT-JAM and other Competitive exams for Chemistry and Chemical Sciences.
Photochemistry is the study of chemical reactions caused by light. Key points include:
- Photochemistry involves light interacting with matter, causing physical or chemical changes.
- Photolysis is the process of carrying out a photochemical reaction using light, usually infrared, visible, or ultraviolet light.
- Important natural photochemical reactions include photosynthesis, photography, ozone formation, and solar energy conversion.
- The photochemical process involves light absorption promoting an electron to a higher energy state, followed by primary processes like isomerization, dissociation, or secondary processes like chain reactions.
- Organic chemistry involves carbon-based compounds, with hydrogen usually being the second most common element. Other common elements are oxygen, nitrogen, sulfur, and halogens.
- Most bonds in organic compounds are covalent, formed through shared electron pairs between atoms. Whether bonds are ionic or covalent depends on the electro-negativity difference between bonded atoms.
- Polar covalent bonds form when there is some electro-negativity difference between atoms, causing the electron cloud to shift slightly towards the more electronegative atom. This gives the atoms partial positive or negative charges.
The electrons which are involved in bond formatio.pdfrakeshankur
The electrons which are involved in bond formation between atoms are found in the
outermost shell (sometimes in the next to the outer-most shell) of the neutral atom; these are
called VALENCE ELECTRONS. The atoms of elements which have only one or two electrons
in their outermost shells (active shells) may lose electrons when they combine with atoms of
other elements. An atom which has lost one or more valence electrons possesses a positive
charge, and is called a POSITIVE ION. The sodium atom loses its one valence electron and
acquires a +1 charge when it enters into chemical combination with an atom of an element such
as chlorine. The magnesium atom may lose its two valence electrons and assume a +2 charge.
Na Na+ + e- The Na symbol to the left of the arrow represents a stable sodium atom while the
Na+ symbol to the right of the arrow represents an unstable sodium ion which has had a single
electron removed. Mg Mg++ + 2e- The Mg symbol to the left of the arrow represents a stable
magnesium atom while the Mg++ symbol to the right of the arrow represents an unstable
magnesium ion which has had two electrons removed. The smaller the number of valence
electrons in the atom, the greater the tendency of the element to lose electrons and thus form
positive ions during chemical combination with atoms of other elements. The energy required to
remove an electron from a neutral atom to form a positive ion is called the IONIZATION
POTENTIAL of the atom. Some metals have small ionization potentials and readily form
positive ions. The nonmetals, which have more electrons in their outer shells than the metals,
have large ionization potentials and show little tendency toward the formation of positive ions.
Atoms which lack one or two electrons of having an outermost shell of eight electrons readily
gain sufficient electrons from certain other atoms, such as sodium and magnesium, to make a full
compliment of eight electrons in the outside shell. Neutral atoms become NEGATIVE IONS by
gaining electrons. The nonmetals, such as Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I),
Oxygen (O), Nitrogen (N) and Sulfur (S), readily form negative ions. Cl + e- Cl- Chlorine,
when in its stable form, possesses seven valence electrons and therefore has the ability to gain
one electron (as represented to the left of the arrow) giving it a negative charge of one when in
its unstable ionic form (as represented to the right of the arrow above). S + 2e- S-2 Sulfur, when
in its stable form, possesses six valence electrons and therefore has the ability to gain two
electrons giving it a negative charge of two when in its unstable ionic form. The attraction of a
neutral atom for electrons is known as its ELECTRON AFFINITY. The nonmetals have high
electron affinities and the metals have very low electron affinities. Thus, mainly the nonmetals
tend to form negative ions during chemical combination. When a positive ion and a negative ion
are brought close together, strong electr.
Pyrolytic elimination reactions involve the application of heat to induce an elimination reaction in an organic substrate without the need for an external base or solvent. This type of elimination proceeds through a concerted, syn-elimination via a cyclic transition state that allows for an intramolecular proton transfer and the formation of a new carbon-carbon double bond. Specific examples of pyrolytic eliminations discussed in the document include the conversion of esters to carboxylic acids and alkenes, eliminations in alicyclic systems, Cope eliminations, sulfoxide eliminations, xanthate pyrolysis, and selenoxide eliminations.
This document summarizes a seminar presentation on dπ-pπ bonds. It introduces that d-orbitals on third period elements can participate in bonding. The eg orbitals can form σ-bonds by overlapping with s and p orbitals, while the t2g orbitals can combine with p orbitals of the same character. However, free atom d-orbital energies are high, the orbitals are diffuse rather than compact, and promotion energies to d-orbital states are around 30-35 eV, making significant d-orbital contributions to bonding unlikely except in certain cases.
Dynamic Stereochemistry and What role does conformation plays on stereochemistry is being exemplified in this presentation. Useful for the Undergraduate and Postgraduates students of Pharmacy, Pharmaceutical Chemistry and Chemical Sciences
Crystal field theory and ligand field theory describe how ligands interact with transition metal complexes. Crystal field theory uses an electrostatic model to explain orbital splitting, while ligand field theory uses a molecular orbital approach. Both theories predict that ligands cause the d orbitals on the metal to split into lower energy t2g and higher energy eg sets. The size of this splitting depends on whether ligands are σ-donors only, π-donors, or π-acceptors. π-Acceptors increase splitting while π-donors decrease it. This explains the spectrochemical series from weak to strong field ligands.
Kinetics of Pyrolysis of acetaldehyde PRUTHVIRAJ K
Jeevankumar M presented a seminar on the pyrolysis of acetaldehyde under the guidance of Mr. Pruthviraj. Pyrolysis is the thermal degradation of compounds in the absence of oxygen above the boiling point of water. The pyrolysis of acetaldehyde occurs through a chain reaction, producing methyl radicals and hydrogen. The mechanism involves initiation, propagation, and termination steps. Applying steady-state approximations, the rate law for the pyrolysis of acetaldehyde was determined to be third order with respect to acetaldehyde concentration. Pyrolysis has applications in producing fuels from waste and in industrial processes like steelmaking and syngas production.
Molecular orbital theory(mot) of SF6/CO2/I3-/B2H6sirakash
1) Molecular orbital theory views a molecule as delocalized molecular orbitals formed from linear combinations of atomic orbitals. Bonding molecular orbitals are lower in energy due to constructive interference, while antibonding orbitals are higher in energy due to destructive interference.
2) The document provides examples of applying molecular orbital theory to SF6, CO2, B2H6, and I3- molecules. It describes the atomic orbitals and molecular orbitals formed, including bonding, antibonding, and non-bonding orbitals, and explains how the molecular orbitals rationalize the electronic structures and bonding patterns in these molecules.
APPLICATIONS OF ESR SPECTROSCOPY TO METAL COMPLEXESSANTHANAM V
This document discusses the applications of electron spin resonance (ESR) spectroscopy to study metal complexes. It outlines several key factors that influence the ESR spectra of metal complexes, including the nature of the metal ion, ligands, geometry, number of d electrons, and crystal field effects. It also describes how zero-field splitting and Jahn-Teller distortions can lead to splitting of electronic levels and influence the number and pattern of transitions observed in ESR spectra. Understanding these various effects is important for extracting information about electronic structure and bonding from ESR data of metal complexes.
The Lindemann theory provides an explanation for unimolecular gas-phase reactions. It proposes that:
1) A molecule A acquires sufficient vibrational energy from collisions with other A molecules to form an energized molecule A*.
2) A* can then either lose its energy and revert to A, or it can decompose or isomerize in a subsequent reaction.
3) This process leads to first-order kinetics for the overall reaction rate, consistent with experimental observations of unimolecular reactions.
However, the Lindemann theory has some limitations, as the predicted rate constant versus concentration relationship is hyperbolic rather than linear as observed experimentally. More advanced theories like RRK and Slater were developed to
Metal nitrosyl compounds contain nitric oxide bonded as an NO+ ion, NO- ion, or neutral NO molecule. They can be classified into three classes based on the nitric oxide group present. Metal nitrosyls are coordination compounds where an NO molecule is attached as an NO+ ion to a metal atom or ion. Examples include metal nitrosyl carbonyls such as Co(NO+)(CO)3, metal nitrosyl halides such as Fe(NO+)2I, and metal nitrosyl thio-complexes involving Fe, Co, and Ni metals. These compounds can be prepared through the reaction of nitric oxide with metal compounds like carbonyls, halides, or ferrocyanides. Metal
Electrophilic aromatic substitution is a reaction where an atom attached to an aromatic system is replaced by an electrophile. The aromatic ring attacks the electrophile, forming a carbocation intermediate. This intermediate is stabilized by resonance. A Lewis base then donates electrons back to the ring, restoring aromaticity. Substituents can activate or deactivate the ring by donating or withdrawing electron density. Activating groups make the reaction more likely and direct substitution to the ortho- and para- positions, while deactivating groups have the opposite effects.
The document discusses molecular orbital theory and its application to transition metal complexes. It describes how atomic orbitals of matching symmetry combine to form molecular orbitals, with equal numbers of bonding and antibonding orbitals. Electrons fill the molecular orbitals starting with the lowest energy orbitals. Ligand interactions such as π-accepting and π-donating affect the splitting of orbitals and influence the metal's oxidation state.
The document discusses NMR spectroscopy of various nuclei and their applications to inorganic molecules. It provides details on the natural abundance, spin, magnetic moment, and magnetogyric ratio of common NMR-active nuclei such as 1H, 2H, 11B, 13C, 17O, 19F, 29Si, and 31P. It then discusses the applications of 19F, 29Si, and 31P NMR spectroscopy for structure elucidation of inorganic molecules. Examples are provided to illustrate how NMR chemical shifts and coupling constants can provide information about functional groups, molecular structures, and stereochemistry.
This document discusses electronic spectra of metal complexes. It begins by defining quantum numbers related to electron configuration, such as L (total orbital angular momentum) and l (secondary quantum number). It then describes two main types of electronic transitions in coordination compounds: d-d transitions specific to metals, and charge-transfer transitions. The remainder of the document discusses charge-transfer transitions in more detail, defining ligand-to-metal and metal-to-ligand charge transfer, and how solvent polarity affects these transitions.
The document discusses various types of aliphatic nucleophilic substitution reactions and their mechanisms. It covers SN2 and SN1 mechanisms in detail, providing evidence that supports each. It also discusses borderline cases where reactions have characteristics of both SN1 and SN2, and other mechanisms like SN1', SNi, SET, and addition-elimination that may occur under different conditions. Specific examples of nucleophilic substitution are discussed at allylic, trigonal, and vinylic carbons that may proceed by different pathways than typical SN1 or SN2 reactions.
Acid Base Hydrolysis in Octahedral ComplexesSPCGC AJMER
This document discusses acid and base hydrolysis in octahedral complexes. It covers factors that affect the rate of acid hydrolysis, including the charge on the complex, steric hindrance effects, and the strength of the leaving group. A higher positive charge, more steric hindrance, or stronger metal-leaving group bond each decrease the rate of acid hydrolysis according to first-order kinetics through a dissociative SN1 mechanism. Base hydrolysis of octahedral complexes can proceed by either associative SN2 or dissociative SN1 pathways depending on conditions.
This document presents information on the Tanabe-Sugano diagram, which is used in coordination chemistry to predict absorptions in the UV-visible and IR spectra of coordination compounds. It was developed by Yukito Tanabe and Satoru Sugano in 1954 to explain the absorption spectra of octahedral complex ions. The diagram plots orbital energy as a function of the Racah parameter B versus the ligand field splitting parameter Δo/B. It can be used to determine the ordering of electronic states and predict possible electronic transitions based on parameters like Δo, Racah parameters B and C, symmetry rules, and term symbols of electronic configurations. The diagram has advantages over earlier Orgel diagrams in that it can be applied to
Organic Reaction Mechanism : This topic is very-very important for CSIR-NET, GATE, IIT-JAM and other Competitive exams for Chemistry and Chemical Sciences.
Photochemistry is the study of chemical reactions caused by light. Key points include:
- Photochemistry involves light interacting with matter, causing physical or chemical changes.
- Photolysis is the process of carrying out a photochemical reaction using light, usually infrared, visible, or ultraviolet light.
- Important natural photochemical reactions include photosynthesis, photography, ozone formation, and solar energy conversion.
- The photochemical process involves light absorption promoting an electron to a higher energy state, followed by primary processes like isomerization, dissociation, or secondary processes like chain reactions.
- Organic chemistry involves carbon-based compounds, with hydrogen usually being the second most common element. Other common elements are oxygen, nitrogen, sulfur, and halogens.
- Most bonds in organic compounds are covalent, formed through shared electron pairs between atoms. Whether bonds are ionic or covalent depends on the electro-negativity difference between bonded atoms.
- Polar covalent bonds form when there is some electro-negativity difference between atoms, causing the electron cloud to shift slightly towards the more electronegative atom. This gives the atoms partial positive or negative charges.
The electrons which are involved in bond formatio.pdfrakeshankur
The electrons which are involved in bond formation between atoms are found in the
outermost shell (sometimes in the next to the outer-most shell) of the neutral atom; these are
called VALENCE ELECTRONS. The atoms of elements which have only one or two electrons
in their outermost shells (active shells) may lose electrons when they combine with atoms of
other elements. An atom which has lost one or more valence electrons possesses a positive
charge, and is called a POSITIVE ION. The sodium atom loses its one valence electron and
acquires a +1 charge when it enters into chemical combination with an atom of an element such
as chlorine. The magnesium atom may lose its two valence electrons and assume a +2 charge.
Na Na+ + e- The Na symbol to the left of the arrow represents a stable sodium atom while the
Na+ symbol to the right of the arrow represents an unstable sodium ion which has had a single
electron removed. Mg Mg++ + 2e- The Mg symbol to the left of the arrow represents a stable
magnesium atom while the Mg++ symbol to the right of the arrow represents an unstable
magnesium ion which has had two electrons removed. The smaller the number of valence
electrons in the atom, the greater the tendency of the element to lose electrons and thus form
positive ions during chemical combination with atoms of other elements. The energy required to
remove an electron from a neutral atom to form a positive ion is called the IONIZATION
POTENTIAL of the atom. Some metals have small ionization potentials and readily form
positive ions. The nonmetals, which have more electrons in their outer shells than the metals,
have large ionization potentials and show little tendency toward the formation of positive ions.
Atoms which lack one or two electrons of having an outermost shell of eight electrons readily
gain sufficient electrons from certain other atoms, such as sodium and magnesium, to make a full
compliment of eight electrons in the outside shell. Neutral atoms become NEGATIVE IONS by
gaining electrons. The nonmetals, such as Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I),
Oxygen (O), Nitrogen (N) and Sulfur (S), readily form negative ions. Cl + e- Cl- Chlorine,
when in its stable form, possesses seven valence electrons and therefore has the ability to gain
one electron (as represented to the left of the arrow) giving it a negative charge of one when in
its unstable ionic form (as represented to the right of the arrow above). S + 2e- S-2 Sulfur, when
in its stable form, possesses six valence electrons and therefore has the ability to gain two
electrons giving it a negative charge of two when in its unstable ionic form. The attraction of a
neutral atom for electrons is known as its ELECTRON AFFINITY. The nonmetals have high
electron affinities and the metals have very low electron affinities. Thus, mainly the nonmetals
tend to form negative ions during chemical combination. When a positive ion and a negative ion
are brought close together, strong electr.
A covalent bond involves the sharing of electron pairs between atoms. There are two types of covalent bonding: non-polar, with equal sharing, and polar, with unequal sharing. A non-polar bond forms between like atoms that share electrons equally, while a polar bond forms between different atoms where one atom attracts the electrons more than the other due to differing electronegativity. Examples of non-polar molecules are H2, Cl2, and O2, where the atoms share electrons equally. Examples of polar molecules are HCl and H2O, where the more electronegative atom (Cl or O) attracts the electrons slightly more, giving it a partial negative charge and leaving the other atom with
Lewis symbols and the octet rule are used to represent valence electrons and chemical bonding. Lewis symbols show valence electrons as dots around the element symbol. The octet rule states that atoms bond to gain, lose, or share electrons to achieve an octet of 8 valence electrons. Exceptions include odd total electron molecules, molecules where atoms have less than an octet, and hypervalent molecules where the central atom has more than 8 electrons.
Compounds are substances made of two or more elements that often have different properties than their constituent elements. Atoms bond together in compounds via chemical bonds formed by sharing valence electrons, called covalent bonds. A covalent bond forms when two atoms share one or more pairs of valence electrons, with single bonds sharing one pair and double or triple bonds sharing more pairs. The sharing of electrons leads to stable covalent compounds with properties like low melting and boiling points.
Atoms form chemical bonds to achieve stable electron configurations. They follow the octet rule by gaining, losing, or sharing electrons to acquire eight electrons in their valence shell. There are four main types of chemical bonds: ionic bonds form when electrons are completely transferred between atoms, covalent bonds form when electrons are shared between atoms, and polar and nonpolar covalent bonds differ based on whether the electron sharing is equal or unequal. Chemical bonds determine many properties of compounds including their physical state, solubility, and ability to conduct heat and electricity.
This document discusses polar covalent bonds and acid-base chemistry. It introduces electronegativity and how differences in electronegativity between atoms leads to polar covalent bonds. Bond polarity can be quantified using dipole moments. Resonance structures are discussed as ways to represent delocalized bonding. Brønsted-Lowry acids and bases are defined as proton donors and acceptors. Acid strength is quantified using acidity constants (Ka) and their logarithmic form, pKa values. Organic acids and bases are introduced. Lewis acids and bases are also defined in terms of electron pair acceptance and donation.
This document provides an overview of general and organic chemistry concepts related to carbon atoms. It discusses atomic theory, covalent bonding, chemical formulas, structural classifications of carbon atoms, hybridization, charges and dipoles of organic molecules, isomers, and functional groups. The key topics covered are the electronic configuration and valence of carbon, how carbon forms single, double and triple covalent bonds, molecular, structural and condensed chemical formulas, and the four types of carbon atoms based on their bonding.
CH 4 CHEMICAL BONDING AND MOLECULAR STRUCTURE.pdfLUXMIKANTGIRI
English chapter we will discuss about bonding how the molecules and the ions are in texting as a molecule make the structure there energy their transmission and other
This document defines covalent bonding and discusses different types of covalent bonds. It provides examples of covalent bonds in molecules like H2O and H2. The types of covalent bonds covered are single, double, and triple bonds. Covalent bonds are also classified as polar or nonpolar depending on differences in electronegativity. Key properties of covalent compounds discussed are low melting and boiling points, poor electrical conductivity, flammability for those containing carbon and hydrogen, and soft or brittle solid forms.
Lecture 8.2- Lewis Dot Structures for MoleculesMary Beth Smith
The document discusses ionic and covalent bonding. It explains how to draw Lewis dot structures to show electron sharing between atoms to form single, double or triple covalent bonds. Examples are given of molecules like H2O, NH3, CH4, CO2, and O3 that form different types of covalent bonds through electron sharing.
The document discusses chemical bonding, including:
1. Defining ionic and covalent bonding, and explaining how different types of bonds are formed through electron sharing or transfer.
2. Describing the properties of ionic and covalent compounds, such as high melting points for ionic solids and variable states of matter for covalent substances.
3. Illustrating examples of single, double, and triple covalent bonds through Lewis dot structures of molecules like H2, O2, and N2.
1. Covalent bonds form when two atoms share one or more pairs of valence electrons in order to achieve a stable octet of electrons.
2. Molecules are formed when atoms are bonded together by covalent bonds, and molecular compounds are composed of molecules.
3. Molecular compounds tend to have lower melting and boiling points than ionic compounds and many are gases or liquids at room temperature.
The document discusses different types of covalent bonds:
- Single covalent bonds involve one shared pair of electrons between two nonmetal atoms.
- Double and triple covalent bonds share two or three pairs of electrons respectively.
- Polar covalent bonds occur when electrons are shared unequally between atoms of different electronegativity, giving the atoms partial positive and negative charges. Polar molecules have regions of positive and negative charge.
Atoms combine through chemical bonds to achieve stability. There are different types of chemical bonds: ionic bonds form through electron transfer between metals and non-metals, covalent bonds form through electron sharing between non-metals, and coordinate covalent bonds form through lone pair donation by one atom that is shared by both atoms. The octet rule drives bonding as atoms seek to acquire a stable noble gas configuration by gaining or sharing electrons to complete their outer shell. Hybridization of atomic orbitals also influences molecular geometry and bond angles.
Chemical bonding involves atoms forming stable electronic configurations through gaining, losing or sharing electrons. Ionic bonds form between metals and nonmetals when electrons are transferred, while covalent bonds involve sharing electron pairs between nonmetals to achieve stable octets. Different bond types including ionic, covalent and metallic bonding can be identified based on the participating elements and electron configurations involved.
There are three main types of chemical bonds: ionic, covalent, and metallic. Ionic bonds involve the electrostatic attraction between oppositely charged ions. Covalent bonds involve the sharing of electrons between atoms. Metallic bonds involve metal atoms bonded to several other metal atoms. The strength of bonds can be estimated from bond enthalpy values, which provide the energy required to break chemical bonds. Bond strength increases as bond length decreases.
There are three main types of chemical bonds: ionic, covalent, and metallic. Ionic bonds involve the electrostatic attraction between oppositely charged ions. Covalent bonds involve the sharing of electrons between atoms. Metallic bonds involve metal atoms bonded to several other metal atoms. The strength of bonds can be estimated from bond enthalpies, which measure the energy required to break chemical bonds. Bond strength increases as bond length decreases.
This document provides an overview of chemical bonding. It defines a chemical bond as a force of attraction between atoms or ions that holds atoms together in molecules or compounds. Atoms form bonds to achieve stable electron configurations. There are three main types of bonds: ionic, covalent, and metallic. Ionic bonds form through the transfer of electrons between metals and nonmetals. Covalent bonds form through the sharing of electrons, usually between nonmetals. Metallic bonds involve the pooling of electrons between metal atoms. The document further explores bond formation and properties.
This presentation summarizes student grades in a Computer Applications course taught by Syed Abdul Rafay Qadri. It includes the grading scheme, which based 15% of the grade on quizzes, 15% on assignments, 10% on a team report, and the remaining 60% on tests and a final exam. Charts show the grades of individual students on tests, assignments, and the final total. In discussion, it notes the class includes different types of students but that most worked hard and earned good grades, and commends the instructor for his hard work.
This document contains information from a survey on global warming. It asked questions about causes of global warming, level of concern about it, and whether attending seminars on it are helpful. Most respondents believed global warming is caused by human activities like burning fossil fuels and is a high priority issue. The conclusion confirms global warming poses a major challenge and will impact the climate this century. Solutions proposed include international agreements on emissions and funding clean energy development, while also preparing communities to adapt to changes.
This presentation summarizes the 2013 film 12 Years a Slave, based on the true story of Solomon Northup. It discusses the film's portrayal of slavery in America, focusing on Northup's kidnapping and sale into slavery, his struggle to survive and maintain his dignity over 12 years of cruel treatment by masters, and how his life and that of his family was forever altered. It also identifies the main characters and notes that Northup wrote an autobiographical book on which the film was based.
This document provides an overview of the key components and functions of using a dictionary. It discusses the guide words at the top or bottom of each page that indicate the first and last entry words. Each entry word has a definition, pronunciation, part of speech, meaning, and other information. Synonyms are also included to help build vocabulary. The dictionary helps with correct word usage and provides additional details like syllabication, etymology, variants, and inflections. It is used as a reference book to look up words and understand their intended meanings and usages in different contexts.
This document discusses three strategies for building vocabulary: 1) determining meanings through word formation by examining prefixes, suffixes, and compound words, 2) determining meanings through definitions by understanding how definitions identify a term's class and distinguishing features, and 3) determining meanings through contextual clues by analyzing a word's context and parts of speech to infer its meaning. Specific techniques are outlined for each strategy, like understanding how prefixes and suffixes modify root words or using opposites and associations near an unknown word. The overall message is that these three approaches can help readers guess at the meanings of unfamiliar words.
The document discusses the key parts of a car, including the exterior, lights, interior, brakes, suspension, and engine. It then introduces different types of engines beyond normal fuel engines, such as electric cars which run solely on electricity from rechargeable batteries, and hydrogen cars which use hydrogen as fuel in either an internal combustion engine or fuel cell to power electric motors.
- Organic chemistry deals with carbon-based compounds. Carbon forms covalent bonds with other elements by hybridizing its atomic orbitals.
- Carbon can form single, double or triple bonds depending on whether it undergoes sp3, sp2 or sp hybridization, respectively. This allows carbon to achieve the correct molecular geometry and bond energies.
- The type of bonding (ionic, covalent or coordinate covalent) between elements depends on their difference in electronegativity. Covalent bonds can be nonpolar or polar depending on this difference.
Acrylic fibers are synthetic fibers made from polyacrylonitrile. They are produced through a process involving polymerization, dissolving the polymer in a solvent, extruding it through a spinneret, and coagulating the filaments. Acrylic fibers are used to make clothing, home goods, and industrial materials due to their moisture wicking, colorfastness, warmth, and low cost. Common acrylic clothing includes sweaters, socks, and coats.
Work is defined as a force acting on an object and moving it through a displacement. It is calculated as work equals force times distance (W=Fd). The SI unit for work is the joule. Work can be positive when force and displacement are in the same direction, negative when they are in opposite directions, and zero when the force is perpendicular to displacement. Power is the rate of doing work and is calculated as work divided by time. Energy is the ability to do work and its SI unit is also the joule.
Apparel manufacturing involves a series of steps from cutting fabric to packing the finished garments for retail. The major processes include pre-production such as receiving and preparing fabrics, pattern making, sample manufacturing, cutting, value-added processes like embroidery and printing, stitching and optional washing, finishing, and packing. A clothing manufacturing company is typically organized around these major production processes.
The textile industry is one of the most environmentally harmful industries due to the chemicals and processes used at each stage of production. Major pollutants from textile manufacturing include heavy metals, dyes, chemicals like formaldehyde, and wastewater. Going eco-friendly is important for social responsibility, health concerns of chemicals, and protection of the environment and species from pollution. Prevention of pollution includes reducing waste, reusing materials, recycling, effluent treatment, and adopting green standards and technologies throughout the textile production process.
Apparel manufacturing involves a series of steps from cutting fabric to packing the finished garments for retail. The major processes include pre-production such as receiving and preparing fabrics, pattern making, sample manufacturing, cutting, value-added processes like embroidery and printing, stitching and optional washing, finishing, and packing. A clothing manufacturing company is typically organized around these major production processes.
Acrylic fibers are synthetic fibers made from polyacrylonitrile. They are produced through a process involving polymerization, dissolving the polymer in a solvent, extruding it through a spinneret, and coagulating the filaments. Acrylic fibers are used to make clothing, home goods, and industrial materials due to their moisture wicking, colorfastness, warmth, and low cost. Common acrylic clothing includes sweaters, socks, and coats.
Work is defined as a force acting on an object and moving it through a displacement. It is calculated as work = force x displacement. The SI unit of work is the joule. Work can be positive when force and displacement are in the same direction, zero when they are perpendicular, and negative when opposite. Power is the rate of doing work and is calculated as power = work/time, with the unit watt equal to joule/second. Energy is the ability to do work and has the unit joule.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
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A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
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Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
1. Chemistry for Textile
5. Bonding in organic
compounds
L8: Primary & secondary bonding,
covalent, ionic and coordinate covalent
bonding
2. Organic Chemistry
Organic chemistry includes those
compounds whose main structure is
based on carbon, while hydrogen is the
second most abundant element found
in organic compounds.
The compounds containing only carbon
and hydrogen are called hydrocarbons.
Frequently elements other than carbon
and hydrogen also appear in organic
compounds. These are usually oxygen,
nitrogen, sulfur and halogens
Most of the bonds in an organic
compounds are of covalent nature.
3. Electronic configurations
1A 2A 3A 4A 5A 6A 7A 8A
1
H
1s1
2
He
1s2
3
Li
1s2
2s1
4
Be
1s2
2s2
5
B
1s2
2s22p1
6
C
1s2
2s22p2
7
N
1s2
2s22p3
8
O
1s2
2s22p4
9
F
1s2
2s22p5
10
Ne
1s2
2s22p6
11
Na
[Ne]
3s1
12
Mg
[Ne]
3s2
13
Al
[Ne]
3s23p1
14
Si
[Ne]
3s23p2
15
P
[Ne]
3s23p3
16
S
[Ne]
3s23p4
17
Cl
[Ne]
3s23p5
18
Ar
[Ne]
3s23p6
5. Atomic structure
The hydrogen atom has only
one electron which is present in
the first or K shell. The
hydrogen atom requires one
more electron to complete it’s
duplet.
Atomic number of carbon is 6,
so it has six electrons in all out
of which two reside in the first
shell. The other four electrons
occupy the second (the last)
shell. To become stable it
needs four more electrons to
complete it’s octet.
6. Atomic structure
The shape of atom is spherical like
a ball with the electron cloud
occupying most of the space taken
by the atom. The nucleus of atom
is situated at the center of sphere
and occupies a very small space
as compared to the space
occupied by the electrons. The
electrons around the nucleus are
present in different shells.
The hydrogen atom having a single
electron has only one shell around
the nucleus.
The carbon with six electron has
two electronic shells. The inner
shell contain two electrons and the
outer shell contains four.
7. Why compounds are formed
The atoms whose
outer shell is
incomplete (contains
less than 8 electrons)
are unstable and tend
to react with similar or
dissimilar atoms to
make compounds.
8. Why some compounds are ionic
while others are covalent?
It depends on the
relative electron
attracting power of
the bonding atoms.
9. Electro-negativities of elements
Since the size and the number of protons and electrons varies in atoms of
different elements, their power to attract electrons towards nucleus also
differs. This property of atoms is called electro-negativity and it determines
the nature of bond forming between two atoms. Electro-negativity of some
of the elements is given in table below.
10. Covalent bond
When there is minor or no
difference of electro-negativity
between the bonding atoms,
the atoms only share their
electrons to form the bond.
The resulting bond is called a
covalent bond. The bonded
atoms cannot move away from
each other until the bond
between them breaks.
When there is somewhat
greater difference of electro-
negativity between the bonding
atoms the bond is still covalent
but becomes polar.
H2.2
Cl3.16
H2.2
C2.55
OHO = 3.44
Cl3.16
12. Polar covalent bonds
A covalent bond becomes polar
when there is some difference of
elecro-negativity between the
bonding atoms.
Hydrogen chloride is a covalent
compound but since there is
greater difference of electro-
negativity between these two
atoms, the electron cloud of the
molecular orbital is slightly shifted
towards the more electronegative
atom chlorine and hydrogen is
slightly deprived of electron cloud.
Due to shifting of electron cloud
the chlorine atom acquire a partial
negative charge and hydrogen
acquires a partial positive charge.
Such bonds are called polar
bonds.
13. Effect of varying
Electronegativity on polarity
The polarity in covalent bonds occurs due
to difference of electro-negativity in
bonding atoms.
The strength of polarity varies with varying
difference of electro-negativity, i.e.
increasing difference will increase polarity
and decreasing will decrease polarity.
14. Non polar and polar bonds in
organic compounds
The saturated hydrocarbons like
methane and ethane are non polar
organic compounds. Similarly
unsaturated hydrocarbons like ethene
(or ethylene) propene (or propylene)
are also non polar compounds.
When carbon is bonded to nitrogen or
oxygen the bond becomes polar due
to greater difference of
electronegativity. Acetone and ethyl
amine are polar compounds.
15. Some characteristics of polar and
non-polar covalent compounds
Non-Polar compounds Polar compounds
They have lower melting and
boiling points.
They have higher melting
and boiling points.
Liquid compounds show
greater volatily.
Liquid compounds show
lesser volatility.
They tend to dissolve in non-
polar solvents.
They tend to dissolve in
polar solvents.
They show lower reactivity They show higher reactivity
16. Polar vs non-polar compounds
Methane is a non-polar
compound which occurs
in gaseous form while
methanol is polar and
occurs in liquid form.
Similarly non-polar
ethane is a gaseous
compound while ethanol
is polar and liquid.
17. Ionic bond
When the difference of electro-
negativity becomes too high,
the electron from less
electronegative atom moves to
the more electronegative atom.
Such a bond is called ionic
bond because such
compounds produce ions in
solution.
The ions in solution can move
freely, hence the bonded
atoms move away from each
other.
H2.2
Cl3.16
OHO = 3.44
Na0.90
18. Ionic bond
Hydrogen chloride (HCl) is
a covalent compound
where the difference of
electo-negativity is less
than one, while sodium
chloride (NaCl) is an ionic
compound where the
difference of
electronegativity is more
than 2.
19. Co-ordinate covalent or dative
bond
It is similar to the covalent
bond in that electrons are
shared between the bonding
atoms but the difference is that
both the shared electrons are
donated by only one atom.
Since both the shared
electrons are donated by one
atom, the donor atom becomes
electron deficient and hence
gains positive charge. The
acceptor atom become
electron efficient and gains
negative charge.
This kind of bond has both
ionic and covalent character
20. Co-ordinate covalent or dative
bond
Another interesting example of coordinate covalent or dative bond is
the ammonium ion which is formed when ammonia reacts with
hydrochloric acid to make ammonium chloride.
Hydrogen atom leaves it’s electron with chlorine and makes
coordinate covalent bond with ammonia. The resulting species are
ammonium and chloride ions.
21. Atomic structure
A simple structure of atom implies that all
the electrons in a single atomic orbital
have same energy.
The simple structure of atom does not
however represent a true picture of atom.
It is because even in a single atomic
orbital all the electrons do not have the
same energy level and all atomic orbital
except the first one consist of more than
one sub levels or orbitals which are
designated as s,p,d and f orbitals.
In case of carbon the second (last) shell
cotains two sub-shells namely s and p. S
is of lower energy and p is of higher
energy. Two of the four electrons in last
shell occupy s orbital and the other two
Px and py orbitals.
21
22. Atomic structure
In atomic state the valance
shell of carbon has 2 electrons
in 2s orbital, one electron in
2px orbital and one electron in
2py orbital, while the 2pz
orbital is empty.
In this situation there are only
two unpaired eletrons which
suggests the carbon to be
bivalent.
Hybridization 22
23. Atomic structure
In fact in all carbon
compounds’ the
carbon is found in
tetravalent state.
For e.g. in methane
carbon is in
tetravalent form.
Hybridization 23
24. Hybridization 24
Electronic configuration and
bonding in carbon
Carbon can make four single
bonds with four other species
or one double and two single
bonds with three other species
or one triple bond and one
single with two other species.
Looking at the electronic
configuration it seems difficult
for carbon to make such
bonds. For making one sigma
and one or more pi bonds p
orbitals of both atoms must be
parallel which is not possible
under these conditions.
27. Hybridization 27
Bonding with carbon
Considering the
electronic configuration of
carbon, we see that 2s
orbital is completely filled,
2px and 2py are partially
filled while the 2pz orbital
is empty. Under this
condition carbon can
make only two single
bonds with two other
species.
28. Hybridization 28
Bonding with carbon
On the other hand if we
consider the promotion of
one of the 2s electrons to
the empty 2pz orbital,
four unpaired electrons in
the 2s and 2p orbitals will
be obtained and hence
carbon should now be
able to make four single
bonds with four other
species like hydrogen.
29. Hybridization 29
Bonding with carbon
The problem which now arises
is that the low lying s orbital
will not be able to make an
effective bond with another
species due to hindrance
offered by p orbitals.
Furthermore all the four bonds
will not be of equal bond
energy, however in actual
practice all four single bonds
which carbon makes with four
other similar species, like
hydrogen, are of same energy.
30. Hybridization 30
Hybridization
Carbon can make four single bonds with four separate atoms, two
single bonds and one double bond with three separate atoms or one
single and a triple bond with two separate atoms.
All sigma bonds posses the same bond energy.
This cannot be justified by simply promoting one 2s electron to 2p
orbital.
The solution to this problem was provided by suggesting the idea of
hybridization of 2s and 2p atomic orbitals to give the same number
of hybridized orbitals having the same bond energy and shape.
Hybridization is the mixing up of atomic orbitals of different
energy to give a new set of same number of hybrid orbitals
having same energy.
32. Hybridization 32
sp3 hybridization
When carbon makes four single bonds, one 2s and three
2p orbitals hybridize to produce four hybrid orbitals
called sp3 orbitals.
These four hybrid orbitals have same energy value and
have same bond angles (109.5º), directed towards the
corners of a regular tetrahedron.
35. Hybridization 35
sp2 hybridization
When carbon makes two single bonds and one double
bond, one 2s and two 2p orbitals hybridize to produce
three hybrid orbitals called sp2 orbitals. The third 2p
orbital do not hybridize.
The three hybridized orbitals have the same energy
value and bond angle (120º), while the unhybridized 2p
orbital have different energy value and helps in making
pi (Л) bond.
37. Hybridization 37
sp hybridization
When carbon makes one single bond and one triple bond, one 2s
and one 2p orbital hybridize to produce two hybrid orbitals called sp
orbitals. The two remaining 2p orbitals do not hybridize.
The two hybridized orbitals have the same energy value and the
bond angle between them is 180º, while the unhybridized 2p orbitals
have different energy value and helps in making triple bond.
39. Hybridization 39
Sp3 hybridization in Nitrogen,
Oxygen and Halogens
Nitrogen has three unpaired electrons in its 2p orbitals and two
paired electrons in s orbital. While bonding it hybridizes to sp3
geometry making three single bonds with other species.
Oxygen has two unpaired electrons in its 2p orbitals and four
electrons in two pairs occupying 2s and one of the 2p orbitals.
While bonding it hybridizes to sp3 geometry making two single
bonds with other species.
Halogens have one unpaired electron in its 2p orbital and six
electrons in three pairs occupying 2s and two of the 2p orbitals.
While bonding it hybridizes to sp3 geometry making one single
bonds with another specie.
41. Hybridization 41
sp2 hybridization in nitrogen and
oxygen
Nitrogen has three unpaired electrons in its 2p orbitals and two paired electrons in 2s
orbital. While making double bond it hybridizes to sp2 geometry making two sigma
bond and one pi bond with other species.
Oxygen has two unpaired electrons in its 2p orbitals and four electrons as two pairs
occupying 2s and one of the 2p orbitals. While making double bond it hybridizes to
sp2 geometry forming one sigma and one pi bond with the other specie.
42. Hybridization 42
sp hybridization in nitrogen
Nitrogen has three unpaired electrons in its 2p
orbitals and two paired electrons in 2s orbital.
While making triple bond it hybridizes to sp
geometry making one sigma bond and two pi
bonds with the other specie.
43. Primary and secondary bonding
A primary bond is a true bond
which is formed by sharing of
electrons between two atoms
or by transfer of an electron
from one atom to the other.
Primary bonds are covalent,
ionic and coordinate covalent
or dative bonds.
A secondary bond on the other
hand is one where no true
sharing of electrons or transfer
does occur. Examples of
secondary bonding are
hydrogen bonding, dipole-
dipole interaction, Van der
Waal’s forces etc.