The document discusses concepts related to molecular bonding including:
- Electrons fill the lowest available energy orbitals according to the Aufbau principle and Pauli exclusion principle.
- Hydrogen has 1 electron in the 1s orbital. Helium has 2 electrons with opposite spins in the 1s orbital.
- Lithium has 2 electrons in the 1s orbital and 1 electron in the 2s orbital.
- Boron has 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, and 1 electron in the 2px orbital.
- Carbon has 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, and 2 electrons in the 2px and 2py
Lattice energy refers to the energy released when separate ions in the gas phase form an ionic crystal lattice. It can be calculated theoretically using the Born-Landé equation or experimentally using the Born-Haber cycle. The Born-Landé equation considers the electrostatic attraction and repulsive forces between ions, while the Born-Haber cycle uses standard enthalpy data and Hess's law. Lattice energy depends on factors like ion charge and size - higher charge or smaller ions lead to stronger electrostatic forces and higher lattice energy. Lattice energy is an important concept for understanding the properties and stability of ionic compounds.
This document discusses the index of hydrogen deficiency (IHD), which counts the number of hydrogen molecules needed to convert a molecule to its saturated form. It provides the equation for calculating IHD based on the molecular formula. Several example molecules are given along with their IHD values. The document also provides 15 problems giving NMR data and asking readers to determine the structure and/or IHD of compounds. The problems cover 1H and 13C NMR data for various organic molecules.
This document provides an introduction to nuclear physics. It discusses the history and development of the field, from the discovery of radioactivity and the electron in the early 20th century to the proposal of the liquid drop model and development of the semi-empirical mass formula to describe nuclear structure. Key events discussed include Rutherford's discovery of the nuclear model of the atom, the discovery of the neutron by Chadwick, and Yukawa's proposal of the meson to explain nuclear forces. The introduction concludes by outlining the chapters to follow on topics like nuclear decay, fusion, fission, and reactor physics.
1) The document discusses two chemical reactions: reaction (1) of CH4 and O2 producing CO2 and H2O, and reaction (2) of CH4 and CO2 producing 2CO and 2H2.
2) Thermodynamic properties such as enthalpy (H) and Gibbs free energy (G) are introduced to explain why reaction (1) is exothermic and proceeds at 400K, while reaction (2) is endothermic and does not proceed at 400K.
3) The concepts of chemical equilibrium are then covered, noting that reactions may stop before reactants are fully consumed, with the ratio of products to reactants (reaction quotient) equaling the equilibrium constant (K
Polarity in molecules arises from differences in electronegativity between atoms. Polar molecules have partial positive and negative charges separated within the molecule. Water is a common example of a polar molecule due to the oxygen atom's higher electronegativity relative to the hydrogen atoms. Non-polar molecules have electron distribution that symmetrically cancels out partial charges. Dipole moment measures a molecule's polarity as a function of the distance and magnitude of separated partial charges. Common polar molecules with dipole moments include water and carbon dioxide.
This document provides instructions for a chemistry test. It states that the test booklet contains 145 multiple choice questions divided into parts A, B and C, with maximum marks of 200. It provides instructions on answering the required number of questions in each part and filling in personal details on the answer sheet. It also specifies the marking scheme and that calculators are not permitted. The invigilator's role in verifying candidate details is mentioned.
The document provides information about determining the polarity of molecules based on their structure. It discusses that ethane (C2H6) and ethene (C2H4) have non-polar covalent bonds since the electron sharing is equal, while molecules with unequal electron sharing between atoms with different electronegativity can result in polar bonds. It also explains that a molecule is polar if it has polar bonds and asymmetric structure, but non-polar if it has symmetrical structure or only non-polar bonds. Examples of polar molecules discussed include H2O, NH3, and HCN.
Lattice energy refers to the energy released when separate ions in the gas phase form an ionic crystal lattice. It can be calculated theoretically using the Born-Landé equation or experimentally using the Born-Haber cycle. The Born-Landé equation considers the electrostatic attraction and repulsive forces between ions, while the Born-Haber cycle uses standard enthalpy data and Hess's law. Lattice energy depends on factors like ion charge and size - higher charge or smaller ions lead to stronger electrostatic forces and higher lattice energy. Lattice energy is an important concept for understanding the properties and stability of ionic compounds.
This document discusses the index of hydrogen deficiency (IHD), which counts the number of hydrogen molecules needed to convert a molecule to its saturated form. It provides the equation for calculating IHD based on the molecular formula. Several example molecules are given along with their IHD values. The document also provides 15 problems giving NMR data and asking readers to determine the structure and/or IHD of compounds. The problems cover 1H and 13C NMR data for various organic molecules.
This document provides an introduction to nuclear physics. It discusses the history and development of the field, from the discovery of radioactivity and the electron in the early 20th century to the proposal of the liquid drop model and development of the semi-empirical mass formula to describe nuclear structure. Key events discussed include Rutherford's discovery of the nuclear model of the atom, the discovery of the neutron by Chadwick, and Yukawa's proposal of the meson to explain nuclear forces. The introduction concludes by outlining the chapters to follow on topics like nuclear decay, fusion, fission, and reactor physics.
1) The document discusses two chemical reactions: reaction (1) of CH4 and O2 producing CO2 and H2O, and reaction (2) of CH4 and CO2 producing 2CO and 2H2.
2) Thermodynamic properties such as enthalpy (H) and Gibbs free energy (G) are introduced to explain why reaction (1) is exothermic and proceeds at 400K, while reaction (2) is endothermic and does not proceed at 400K.
3) The concepts of chemical equilibrium are then covered, noting that reactions may stop before reactants are fully consumed, with the ratio of products to reactants (reaction quotient) equaling the equilibrium constant (K
Polarity in molecules arises from differences in electronegativity between atoms. Polar molecules have partial positive and negative charges separated within the molecule. Water is a common example of a polar molecule due to the oxygen atom's higher electronegativity relative to the hydrogen atoms. Non-polar molecules have electron distribution that symmetrically cancels out partial charges. Dipole moment measures a molecule's polarity as a function of the distance and magnitude of separated partial charges. Common polar molecules with dipole moments include water and carbon dioxide.
This document provides instructions for a chemistry test. It states that the test booklet contains 145 multiple choice questions divided into parts A, B and C, with maximum marks of 200. It provides instructions on answering the required number of questions in each part and filling in personal details on the answer sheet. It also specifies the marking scheme and that calculators are not permitted. The invigilator's role in verifying candidate details is mentioned.
The document provides information about determining the polarity of molecules based on their structure. It discusses that ethane (C2H6) and ethene (C2H4) have non-polar covalent bonds since the electron sharing is equal, while molecules with unequal electron sharing between atoms with different electronegativity can result in polar bonds. It also explains that a molecule is polar if it has polar bonds and asymmetric structure, but non-polar if it has symmetrical structure or only non-polar bonds. Examples of polar molecules discussed include H2O, NH3, and HCN.
This would enable students to explain the emission spectrum of hydrogen using the Bohr model of the hydrogen atom; calculate the energy, wavelength, and frequencies involved in the electron transitions in the hydrogen atom; relate the emission spectra to common occurrences like fireworks and neon lights; and describe the Bohr model of the atom and the inadequacies of the Bohr model.
1. Nuclear models like the liquid drop model and shell model describe aspects of nuclear structure and behavior. The liquid drop model treats the nucleus like a liquid drop while the shell model treats nucleons as moving independently in nuclear orbits.
2. The shell model explains nuclear magic numbers and properties like spin and parity. Magic numbers correspond to nuclear stability when the number of protons or neutrons equals 2, 8, 20, 28, 50, 82, etc. The shell model accounts for magic numbers in terms of closed nuclear shells.
3. While insightful, nuclear models have limitations and do not fully describe all nuclear phenomena. The liquid drop model cannot explain magic numbers while the shell model fails to explain the stability of certain
This chapter discusses carbocations, which are positively charged carbon-containing ions that are highly reactive intermediates in organic chemistry. Carbocations have six electrons in the outer shell of the central carbon atom. They are stabilized by electron-donating groups and destabilized by electron-withdrawing groups. Carbocations undergo various reactions including reactions with nucleophiles, elimination reactions, rearrangement reactions, and additions to unsaturated systems. Non-classical carbocations are also discussed.
The document is a slide presentation on chapter 1 of a general chemistry textbook. Chapter 1 covers fundamental topics like the properties and states of matter, measurement units, and dimensional analysis. It defines physical and chemical properties, classifies matter as elements, compounds, and mixtures, and discusses techniques for separating mixtures. Key concepts explained include significant figures, temperature scales, volume, density, and unit conversions. The presentation concludes with sample end-of-chapter questions.
This document discusses isotopes and nuclear reactions. It defines isotopes as atoms of the same element with different numbers of neutrons. It also describes how atomic mass is calculated based on isotope abundances. The document then discusses four types of nuclear reactions: fusion, fission, alpha decay, and beta decay. It provides examples of writing balanced nuclear equations and calculating half-life. Artificial transmutation and uses of nuclear technology like reactors and weapons are also summarized.
Colour centres are point defects or defect clusters in crystal lattices that cause the material to change color. They occur when electrons or holes become trapped at defect sites. Common examples are the F-centre in alkali halides, which forms when an electron is trapped at a halide ion vacancy, and the H-centre and V-centre in alkali halides, which involve trapped holes. Defect clusters can also form through the interaction of multiple point defects, such as pairs or groups of F-centres. The defects cause color changes by absorbing visible light and exciting trapped electrons or holes to higher energy states.
This document is a chapter from a general chemistry textbook about atoms and the atomic theory. It discusses early discoveries in chemistry that led to modern atomic theory, including Dalton's atomic theory. It also describes experiments that showed atoms are made of a small, dense nucleus surrounded by electrons, including discovery of the electron, proton, and neutron. The chapter concludes by explaining isotopes, atomic numbers, mass numbers, and how the mole is used to relate mass to number of particles.
1) Mulliken's electronegativity is defined as the arithmetic mean of an atom's first ionization energy and electron affinity.
2) Mulliken's electronegativity is approximately 2.8 times greater than Pauling electronegativity.
3) Mulliken's electronegativity increases across a period and decreases down a group in the periodic table due to trends in ionization energy and electron affinity.
1) Atoms have discrete energy levels that electrons can occupy. Electrons prefer the lowest energy level.
2) Excitation energy is the energy needed for an electron to jump to a higher energy level when absorbing a photon. Ionization energy is the energy needed for an electron to escape the atom.
3) Hydrogen emission spectra occur when electrons fall from excited states and emit photons of characteristic wavelengths, such as the Balmer series in visible light. Absorption spectra show dark lines where light is absorbed by electrons jumping to excited states.
This document provides an overview of statistical mechanics. It defines microstates and macrostates, and explains that statistical mechanics studies systems with many microstates corresponding to a given macrostate. The Boltzmann distribution is derived, which gives the probability of finding a system in a particular microstate as being proportional to the exponential of the negative of the energy of that microstate divided by the temperature. Maxwell-Boltzmann statistics are described as applying to classical distinguishable particles, yielding the Maxwell-Boltzmann distribution. References for further reading are also included.
Types Of Chemical Bonds- Ionic Bond,Covalent Bonds,Coordinate Bonds, Basic In...Anjali Bhardwaj
The document discusses different types of chemical bonds formed by atoms to achieve stable inert gas electronic configurations:
1) Ionic bonds occur through complete electron transfer between atoms, making one positively charged and one negatively charged. The ions are then held together by electrostatic attraction.
2) Covalent bonds involve sharing of electrons between atoms of similar electronegativity to attain stable configurations.
3) Coordinate bonds are a type of covalent bond where both shared electrons are donated by one atom to an acceptor atom in need of electrons.
1. The document discusses the development of atomic spectroscopy from 1860 to 1913, including Balmer's empirical formula for the emission spectrum of hydrogen and Bohr's theoretical model of the atom.
2. Bohr postulated that electrons orbit in stable, quantized energy levels and emit or absorb photons of specific frequencies when transitioning between levels.
3. Bohr's model accounted for the Rydberg formula and emission spectrum of hydrogen and was later extended to ions of other elements.
1. Nuclear magnetic resonance spectroscopy uses radio waves to analyze organic molecules by determining the carbon-hydrogen frameworks and identifying different types of hydrogen and carbon atoms.
2. 1H NMR determines the type and number of hydrogen atoms in a molecule, while 13C NMR determines the types of carbon atoms. The frequencies at which different protons and carbons absorb radio waves depends on their electronic environments.
3. Modern NMR spectrometers use a constant magnetic field and scan a range of radio frequencies to resonate various nuclear spins. This resonance provides information about molecular structure through chemical shifts and spin-spin coupling patterns.
The document provides an introduction to key concepts in electrochemistry including oxidation/reduction reactions, oxidation numbers, and definitions of terms like oxidizing agent and reducing agent. It then discusses rules for assigning oxidation numbers, types of redox reactions like disproportionation, electrochemical cells, and how to determine the potential of a cell.
The document discusses the concept of effective nuclear charge. It explains that the actual charge experienced by valence electrons is less than the true nuclear charge due to shielding by inner electrons. This decreased charge is called the effective nuclear charge (Zeff). Slater's rules provide a method to calculate the screening constant σ and thus determine Zeff. The concept of Zeff is applied to explain trends in ionization energy, filling of electron shells, and properties of cations, anions, and across the periodic table.
Classical mechanics vs quantum mechanicsZahid Mehmood
Classical mechanics can explain motion based on Newton's laws of forces and particles. However, experiments at the atomic scale produced results inconsistent with classical theory. Max Planck explained blackbody radiation by quantizing electromagnetic radiation. Later, experiments showed matter also exhibits wave-particle duality, requiring new theories like quantum mechanics.
Chapter 6.1 : Introduction to Chemical BondingChris Foltz
This document discusses chemical bonding. It defines chemical bonds as how most atoms are joined together in nature. It describes the two main types of chemical bonds: ionic bonding which results from the transfer of electrons between ions, and covalent bonding which results from the sharing of electron pairs between atoms. Atoms form chemical bonds to decrease their potential energy and become more stable. Bonds are rarely purely ionic or covalent, but instead exist on a spectrum depending on the electronegativity difference between the atoms.
The document discusses intermolecular forces, which are the attractive forces between molecules. It defines key terms needed to understand intermolecular forces, such as bond dipoles resulting from the unequal sharing of electrons in polar covalent bonds. Molecular properties are influenced by both intramolecular bonds and intermolecular forces. Inductive effects cause polarization of bonds within and between molecules. Electron-withdrawing groups increase molecular polarity through induction, while electron-donating groups decrease polarity. These intermolecular forces, along with molecular shape and polarity, determine critical physical properties like boiling points and solubility.
The document provides information about molecular bonding, including bond strength, bond polarization, and resonance. It discusses how bond strength decreases from triple to double to single bonds. It also explains that polar covalent bonds have electrons predominantly located on one atom due to differences in electronegativity. Resonance structures are presented as alternative Lewis structures that represent different locations of electrons in a molecule, with the actual structure being a resonance hybrid that is an average of the contributing structures. Nitromethane is used as an example to illustrate these concepts.
This would enable students to explain the emission spectrum of hydrogen using the Bohr model of the hydrogen atom; calculate the energy, wavelength, and frequencies involved in the electron transitions in the hydrogen atom; relate the emission spectra to common occurrences like fireworks and neon lights; and describe the Bohr model of the atom and the inadequacies of the Bohr model.
1. Nuclear models like the liquid drop model and shell model describe aspects of nuclear structure and behavior. The liquid drop model treats the nucleus like a liquid drop while the shell model treats nucleons as moving independently in nuclear orbits.
2. The shell model explains nuclear magic numbers and properties like spin and parity. Magic numbers correspond to nuclear stability when the number of protons or neutrons equals 2, 8, 20, 28, 50, 82, etc. The shell model accounts for magic numbers in terms of closed nuclear shells.
3. While insightful, nuclear models have limitations and do not fully describe all nuclear phenomena. The liquid drop model cannot explain magic numbers while the shell model fails to explain the stability of certain
This chapter discusses carbocations, which are positively charged carbon-containing ions that are highly reactive intermediates in organic chemistry. Carbocations have six electrons in the outer shell of the central carbon atom. They are stabilized by electron-donating groups and destabilized by electron-withdrawing groups. Carbocations undergo various reactions including reactions with nucleophiles, elimination reactions, rearrangement reactions, and additions to unsaturated systems. Non-classical carbocations are also discussed.
The document is a slide presentation on chapter 1 of a general chemistry textbook. Chapter 1 covers fundamental topics like the properties and states of matter, measurement units, and dimensional analysis. It defines physical and chemical properties, classifies matter as elements, compounds, and mixtures, and discusses techniques for separating mixtures. Key concepts explained include significant figures, temperature scales, volume, density, and unit conversions. The presentation concludes with sample end-of-chapter questions.
This document discusses isotopes and nuclear reactions. It defines isotopes as atoms of the same element with different numbers of neutrons. It also describes how atomic mass is calculated based on isotope abundances. The document then discusses four types of nuclear reactions: fusion, fission, alpha decay, and beta decay. It provides examples of writing balanced nuclear equations and calculating half-life. Artificial transmutation and uses of nuclear technology like reactors and weapons are also summarized.
Colour centres are point defects or defect clusters in crystal lattices that cause the material to change color. They occur when electrons or holes become trapped at defect sites. Common examples are the F-centre in alkali halides, which forms when an electron is trapped at a halide ion vacancy, and the H-centre and V-centre in alkali halides, which involve trapped holes. Defect clusters can also form through the interaction of multiple point defects, such as pairs or groups of F-centres. The defects cause color changes by absorbing visible light and exciting trapped electrons or holes to higher energy states.
This document is a chapter from a general chemistry textbook about atoms and the atomic theory. It discusses early discoveries in chemistry that led to modern atomic theory, including Dalton's atomic theory. It also describes experiments that showed atoms are made of a small, dense nucleus surrounded by electrons, including discovery of the electron, proton, and neutron. The chapter concludes by explaining isotopes, atomic numbers, mass numbers, and how the mole is used to relate mass to number of particles.
1) Mulliken's electronegativity is defined as the arithmetic mean of an atom's first ionization energy and electron affinity.
2) Mulliken's electronegativity is approximately 2.8 times greater than Pauling electronegativity.
3) Mulliken's electronegativity increases across a period and decreases down a group in the periodic table due to trends in ionization energy and electron affinity.
1) Atoms have discrete energy levels that electrons can occupy. Electrons prefer the lowest energy level.
2) Excitation energy is the energy needed for an electron to jump to a higher energy level when absorbing a photon. Ionization energy is the energy needed for an electron to escape the atom.
3) Hydrogen emission spectra occur when electrons fall from excited states and emit photons of characteristic wavelengths, such as the Balmer series in visible light. Absorption spectra show dark lines where light is absorbed by electrons jumping to excited states.
This document provides an overview of statistical mechanics. It defines microstates and macrostates, and explains that statistical mechanics studies systems with many microstates corresponding to a given macrostate. The Boltzmann distribution is derived, which gives the probability of finding a system in a particular microstate as being proportional to the exponential of the negative of the energy of that microstate divided by the temperature. Maxwell-Boltzmann statistics are described as applying to classical distinguishable particles, yielding the Maxwell-Boltzmann distribution. References for further reading are also included.
Types Of Chemical Bonds- Ionic Bond,Covalent Bonds,Coordinate Bonds, Basic In...Anjali Bhardwaj
The document discusses different types of chemical bonds formed by atoms to achieve stable inert gas electronic configurations:
1) Ionic bonds occur through complete electron transfer between atoms, making one positively charged and one negatively charged. The ions are then held together by electrostatic attraction.
2) Covalent bonds involve sharing of electrons between atoms of similar electronegativity to attain stable configurations.
3) Coordinate bonds are a type of covalent bond where both shared electrons are donated by one atom to an acceptor atom in need of electrons.
1. The document discusses the development of atomic spectroscopy from 1860 to 1913, including Balmer's empirical formula for the emission spectrum of hydrogen and Bohr's theoretical model of the atom.
2. Bohr postulated that electrons orbit in stable, quantized energy levels and emit or absorb photons of specific frequencies when transitioning between levels.
3. Bohr's model accounted for the Rydberg formula and emission spectrum of hydrogen and was later extended to ions of other elements.
1. Nuclear magnetic resonance spectroscopy uses radio waves to analyze organic molecules by determining the carbon-hydrogen frameworks and identifying different types of hydrogen and carbon atoms.
2. 1H NMR determines the type and number of hydrogen atoms in a molecule, while 13C NMR determines the types of carbon atoms. The frequencies at which different protons and carbons absorb radio waves depends on their electronic environments.
3. Modern NMR spectrometers use a constant magnetic field and scan a range of radio frequencies to resonate various nuclear spins. This resonance provides information about molecular structure through chemical shifts and spin-spin coupling patterns.
The document provides an introduction to key concepts in electrochemistry including oxidation/reduction reactions, oxidation numbers, and definitions of terms like oxidizing agent and reducing agent. It then discusses rules for assigning oxidation numbers, types of redox reactions like disproportionation, electrochemical cells, and how to determine the potential of a cell.
The document discusses the concept of effective nuclear charge. It explains that the actual charge experienced by valence electrons is less than the true nuclear charge due to shielding by inner electrons. This decreased charge is called the effective nuclear charge (Zeff). Slater's rules provide a method to calculate the screening constant σ and thus determine Zeff. The concept of Zeff is applied to explain trends in ionization energy, filling of electron shells, and properties of cations, anions, and across the periodic table.
Classical mechanics vs quantum mechanicsZahid Mehmood
Classical mechanics can explain motion based on Newton's laws of forces and particles. However, experiments at the atomic scale produced results inconsistent with classical theory. Max Planck explained blackbody radiation by quantizing electromagnetic radiation. Later, experiments showed matter also exhibits wave-particle duality, requiring new theories like quantum mechanics.
Chapter 6.1 : Introduction to Chemical BondingChris Foltz
This document discusses chemical bonding. It defines chemical bonds as how most atoms are joined together in nature. It describes the two main types of chemical bonds: ionic bonding which results from the transfer of electrons between ions, and covalent bonding which results from the sharing of electron pairs between atoms. Atoms form chemical bonds to decrease their potential energy and become more stable. Bonds are rarely purely ionic or covalent, but instead exist on a spectrum depending on the electronegativity difference between the atoms.
The document discusses intermolecular forces, which are the attractive forces between molecules. It defines key terms needed to understand intermolecular forces, such as bond dipoles resulting from the unequal sharing of electrons in polar covalent bonds. Molecular properties are influenced by both intramolecular bonds and intermolecular forces. Inductive effects cause polarization of bonds within and between molecules. Electron-withdrawing groups increase molecular polarity through induction, while electron-donating groups decrease polarity. These intermolecular forces, along with molecular shape and polarity, determine critical physical properties like boiling points and solubility.
The document provides information about molecular bonding, including bond strength, bond polarization, and resonance. It discusses how bond strength decreases from triple to double to single bonds. It also explains that polar covalent bonds have electrons predominantly located on one atom due to differences in electronegativity. Resonance structures are presented as alternative Lewis structures that represent different locations of electrons in a molecule, with the actual structure being a resonance hybrid that is an average of the contributing structures. Nitromethane is used as an example to illustrate these concepts.
The document discusses stereochemistry and different types of isomers. It introduces structural isomers which have different bonding patterns and stereoisomers which have the same bonding but different spatial arrangements. Stereoisomers can be diastereomers or enantiomers. Diastereomers have different physical properties while enantiomers are non-superimposable mirror images and have identical physical properties. The document uses examples like cyclic molecules and decalins to illustrate these concepts.
Infrared spectroscopy and mass spectrometry are two common forms of spectroscopy used to determine molecular structure. Infrared spectroscopy works by shining infrared radiation on a molecule and observing which wavelengths are absorbed, providing clues about its bonds. Mass spectrometry works by firing electrons at molecules to form radical cations, then detecting their mass-to-charge ratios to determine molecular mass and obtain additional structural information. Both techniques provide essential data for elucidating molecular structures.
The document provides information on naming organic molecules, including the steps and rules for assigning IUPAC names. It explains that molecules are named using a systematic approach with four main components:
1. The parent chain, which is the longest continuous carbon chain containing the functional group.
2. The suffix for the major functional group, which is given the lowest possible number.
3. Prefixes indicating any substituents or minor functional groups, listed in alphabetical order with their position numbers.
4. The order of the name, which follows alphabetical order except for descriptors like tert which are ignored. Examples are provided to illustrate the naming process.
1) The document discusses molecular conformations, which are different shapes of the same molecule caused by bond rotation.
2) Ethane is used as a simple example to illustrate how the energy of a molecule changes with dihedral angle. The staggered conformation is lowest in energy while the eclipsed conformation is highest.
3) Butane is a more complex example with multiple rotatable bonds, leading to four important conformations based on whether groups are staggered or eclipsed. The anti-periplanar staggered conformation is preferred with no strain, while syn-periplanar eclipsed has the most strain.
The document provides an overview of chemical reactions, including:
1) It describes three main types of chemical reactions: substitution reactions, addition reactions, and elimination reactions.
2) It explains that nucleophiles are electron-rich reagents that donate electrons, while electrophiles are electron-poor reagents that accept electrons. Common nucleophiles include anions and molecules with lone pairs, while common electrophiles include protons and elements in Group 13.
3) Using examples, it illustrates how nucleophiles can donate electrons in substitution and addition reactions, and how electrophiles can accept electrons in these reactions.
[1] Nuclear magnetic resonance (NMR) spectroscopy uses radio waves to alter the spin of atomic nuclei within molecules, providing information about molecular structure.
[2] When placed in a strong magnetic field, atomic nuclei such as hydrogen protons align with or against the field. Absorbing radio wave energy can excite the nuclei to a higher energy state.
[3] The energy emitted when the nuclei relax back to the lower energy state is measured by NMR. The chemical environment of each type of nucleus affects the energy level and provides details about molecular bonding and structure.
2012 Orbital Hybrization, Sigma and Pi BondsDavid Young
Carbon forms four equal hybrid orbitals through sp3 hybridization to allow methane to adopt its tetrahedral electron geometry. This involves one s orbital and three p orbitals combining to form four new hybrid orbitals. Sigma bonds are formed by the head-on overlap of hybrid orbitals. Sp2 hybridization with one s and two p orbitals results in trigonal planar geometries like ethene. Pi bonds in double and triple bonds involve overlap of unhybridized p orbitals above and below the sigma bond.
The document summarizes different atomic models including Thomson's model, Bohr's model, Sommerfeld's model, and the vector atom model. Thomson's model proposed that atoms are made up of positive charges and distributed negative charges. Bohr's model introduced allowed orbits and quantized angular momentum. Sommerfeld's model accounted for elliptical orbits and relativistic effects. The vector atom model explained phenomena like the Zeeman and Stark effects using quantum numbers for orbital and spin angular momentum.
1. The document summarizes key concepts from a lecture on alkenes, including their structure, bonding properties, and reactions. It discusses molecular orbital theory and frontier orbital theory as applied to alkenes.
2. Acid-base chemistry concepts are also covered, including Brønsted-Lowry definitions of acids and bases, proton transfer reactions, and factors that influence acidity such as electronegativity and resonance effects. Common acids and their pKa values are listed.
3. Frontier molecular orbital theory is used to predict reactions between reactants by identifying their HOMO and LUMO orbitals and showing curved arrow mechanisms. The roles of acids/bases and electrophiles/nucleophiles
This document provides an overview of bonding basics, including ionic and covalent bonds. Ionic bonds form when a metal transfers electrons to a nonmetal, resulting in oppositely charged ions that attract. Covalent bonds form when atoms share electrons to achieve a full outer shell. Examples show Lewis diagrams and representing the transfer or sharing of electrons to form ionic compounds like KI or covalent molecules like H2O.
Atomos, Teorías Atómicas, Teoría Cuántica, Masa Atómica e Isotoposfernandogc
The document provides information about atoms and their subatomic particles. It defines the atom as the smallest particle of an element that retains its characteristics. It describes atoms as consisting of protons, neutrons, and electrons. The number of protons defines the element and its atomic number, while the total of protons and neutrons is the mass number. Isotopes are atoms of the same element with different numbers of neutrons. Electron configuration diagrams show how electrons are arranged in an atom's energy levels.
The document provides an overview of key topics in chemical bonding covered in Chapter 4, including:
- Electron configurations and valence electrons and how they relate to chemical bonding and stability.
- Drawing electron-dot structures to represent atoms, ions, and molecules.
- The two main types of chemical bonds - ionic bonds formed between ions and covalent bonds formed by shared electron pairs.
- Nomenclature rules for naming ionic and covalent compounds from their formulas and writing formulas from compound names.
- Electronegativity and how it determines if bonds are nonpolar, polar, or ionic.
- The different molecular geometries that result from electron pair repulsion in covalent
Transition metals exhibit similarities within periods and groups due to their d-block electron configurations. They form coordination compounds where the metal ion is surrounded by ligands. Coordination compounds exist as complex ions and counter ions to balance charges. Isomers of coordination compounds can occur due to differences in ligand bonding, spatial arrangements of atoms, or inability to be superimposed on a mirror image. Crystal field theory describes the splitting of d-orbital energies based on ligand field strength. This influences the spin state and colors of transition metal complexes.
The document discusses the structure of matter at the atomic level. It explains that all matter is made up of atoms, which themselves are made of even smaller particles like protons, neutrons, and electrons. The structure of atoms determines their chemical properties and how they interact. Atoms can bond together through the sharing or transfer of valence electrons in their outer shells.
The document summarizes the structure of an atom in 3 paragraphs:
1) It describes the three main subatomic particles - electrons, protons, and neutrons - and their relative masses and charges.
2) It outlines the historical discoveries of these particles, including Thomson discovering electrons in 1900, discoveries of positively charged particles (protons) in the late 1800s, and Chadwick discovering neutrons in 1932.
3) It discusses several historical models of the atom, including Thomson's "plum pudding" model, Rutherford's discovery of the nucleus from alpha scattering experiments, and Bohr's improvement adding discrete electron orbits that explained atomic stability.
Intro chem ch 12 chemical bonding sp08khalidmohmed
Chemical bonds are attractive forces that hold groups of atoms together. There are two main types of bonds: ionic and covalent. Ionic bonds form between metals and nonmetals and involve the transfer of electrons. Covalent bonds form when atoms share electrons. The octet rule states that atoms seek to obtain a noble gas configuration by gaining, losing, or sharing electrons. Lewis structures can represent ionic and covalent bonding using dots and lines to show valence electrons. Molecular shape is determined by valence shell electron pair repulsion theory.
Chemical bonds are attractive forces that hold groups of atoms together. There are two main types of bonds: ionic and covalent. Ionic bonds form between metals and nonmetals via electrostatic attraction as electrons are transferred. Covalent bonds form when atoms share electrons. Lewis structures use dots and lines to represent valence electrons and show how atoms bond to achieve stable electron configurations like the octet rule.
The document provides instructions for students to complete a packet on chemical bonding, including drawing Lewis dot diagrams and determining bond type using electronegativity values. Students are asked to draw Bohr models and complete notes up to page 6 for homework. Materials and scheduling for assessments are also included.
The document discusses covalent bonding and Lewis dot structures. It provides examples of how atoms share electrons to form covalent bonds in order to achieve stable octet configurations. Diatomic molecules such as H2, O2, N2, F2, and many biological molecules form covalent bonds in this way. Lewis dot structures are used to represent how valence electrons are arranged among atoms in molecules. Resonance structures can occur when more than one valid Lewis structure can be drawn for a molecule.
A battery releases electromotive force (EMF) to induce an electric current in a circuit by transferring electrical energy from the chemical energy stored within it through electrochemical reactions between its electrodes and electrolytes. Batteries come in wet and dry forms, with wet cells using a liquid electrolyte while dry cells use paste, and rechargeable secondary batteries can be recharged by applying electric current to reverse the chemical reactions unlike disposable primary batteries. The water level in lead-acid batteries should be topped up after charging to the designated level.
1. The document discusses different types of chemical bonding including ionic bonding, covalent bonding, and metallic bonding.
2. Ionic bonding occurs when atoms transfer electrons to form oppositely charged ions that are then attracted via electrostatic forces, such as in sodium chloride (NaCl).
3. Covalent bonding involves the sharing of electron pairs between atoms to form molecular compounds, like in water (H2O) and methane (CH4).
Ch. 3 elements and the periodic table(sec.1&2)Hamdy Karim
The document describes the atomic structure of elements including protons, neutrons, electrons and isotopes. It explains how elements are arranged in the periodic table according to their atomic number and properties, with elements in the same group having similar properties. The periodic table is then used to describe the characteristics and properties of different groups of elements including metals, non-metals, transition metals, and synthetic heavy elements.
The document discusses the structure of atoms, including atomic orbitals and hybridization. It provides examples of sp, sp2, and sp3 hybridization in carbon and nitrogen. Sp hybridization forms two equivalent orbitals and is seen in acetylene. Sp2 hybridization forms three equivalent orbitals and one unhybridized p orbital, as seen in ethene. Sp3 hybridization forms four equivalent orbitals, as in methane and ammonia. The document is intended to explain these concepts for an audience learning about organic chemistry.
1) The document discusses molecular geometry and bonding theories, including different types of chemical bonds, molecular structure, and hybrid orbital theory.
2) Chemical bonds include covalent bonds formed by electron sharing, ionic bonds formed by electron transfer between metals and nonmetals, and metallic bonds between pure metals. Molecular structure is determined by valence shell electron pair repulsion theory.
3) Hybrid orbital theory proposes that atomic orbitals can mix or hybridize to adopt geometries that optimize bonding. Examples discussed include sp, sp2, and sp3 hybrid orbitals that give rise to linear, trigonal planar, and tetrahedral geometries respectively.
This document discusses chemical bonding concepts including:
- Valence electrons and Lewis dot structures for representative elements.
- Ionic bonding formation through electron transfer between atoms.
- Covalent bonding through electron sharing between atoms.
- Factors that influence lattice energy of ionic compounds such as charge and ion size.
- Drawing Lewis structures and evaluating formal charges to determine most likely structures.
A look at epothilone A as it includes examples of many different forms of asymmetric synthesis. Also includes a little bit about ring-closing metathesis.
This document summarizes MacMillan's total synthesis of callipeltoside C, which employs organocatalysis and several interesting chemical transformations. The retrosynthesis splits the molecule into three fragments - the macrocyclic lactone core, carbohydrate, and a third segment prepared using organocatalysis. The forward synthesis couples these fragments in a convergent manner, with key steps including a Negishi carbometallation, organocatalytic hydroxylation, Semmelhack reaction to form the tetrahydropyran ring, and glycosidation to join the sugar moiety. The synthesis highlights the utility of retrosynthesis in simplifying complex targets and total synthesis in confirming the structure of natural products.
Gives an introduction to total synthesis and why we do it (which reminds me, I must add a picture of Everest, as I think the fact that 'it is there' is the main reason for most syntheses). Then to introduce the topic with a reasonably simple synthesis, we will look at an example of the synthesis of Tamiflu.
This document discusses organocatalysis, which uses small organic molecules rather than metals to catalyze chemical reactions. It notes the benefits of organocatalysis such as robust catalysts, new reaction types, and cleaner chemistry. Specific examples are provided of reactions catalyzed by proline, imidazolidinones, thioureas, and phosphoric acids. These catalysts form reactive intermediates like enamines and iminium ions to activate substrates for nucleophilic attack. Overall, organocatalysis is presented as a useful tool for synthetic chemists to address issues like solvent use, purification, and atom economy.
This is the biggy, the one everyone wants to achieve. Here we will be looking at metal-based chiral catalysis. We will concentrate on bisoxazoline-based Lewis acid catalysis and then look at reductions before finishing with the ubiquitous Sharpless epoxidation and dihydroxylation.
Use of stoichiometric amounts of a chiral source. The usual suspects will be discussed, including borane reagents (mostly pinene derivatives) and the Brown allylation.
Self explanatory really, this lecture looks at chiral auxiliaries. We will concentrate on oxazolidinones in alkylations, aldol reaction and the Diels-Alder reaction. There will be a couple examples of other auxiliaries.
1) The document discusses various methods of substrate control in organic reactions, focusing on how substrate conformation can influence diastereoselectivity. Allylic 1,3-strain (A1,3 strain), where substituents on the first and third carbons interact sterically, is a key concept.
2) Reactions like epoxidation and hydroboration are often highly diastereoselective when the substrate adopts a conformation that positions the smallest substituent syn to the reactive double bond to minimize A1,3 strain. The reagent then approaches from the least hindered face.
3) Directed reactions use hydrogen bonding or coordination to deliver the reagent to one
General introduction to the course followed by a basic introduction to asymmetric or stereoselective Synthesis. Then starting the course proper by looking at substrate control.
The document discusses the total synthesis of ibuprofen and the antihypertensive drug valsartan from starting materials.
For ibuprofen, a retrosynthetic analysis is performed to arrive at reactions to connect the starting materials in the forward sense. For valsartan, a retrosynthesis is proposed using a carboxylic acid starting material and an amine.
Lastly, a retrosynthesis is proposed for an asymmetric molecule shown, dividing it into two subunits that can be synthesized and coupled using reactions like Mitsunobu, Brown allylation/crotylation, and peptide coupling.
More problems covering asymmetric synthesis. This time with examples of substrate control, chiral reagents, and chiral catalysis. Also another example of a synthesis.
1. The document describes several organic reactions and asks questions about determining product structures and rationalizing stereochemical outcomes.
2. Key concepts discussed include: conformational analysis to determine reactivity; Cram chelation control to set stereochemistry; Ireland-Claisen rearrangements maintaining configuration; and using chiral auxiliaries to induce diastereoselectivity through chelation.
3. Rationalizations of stereochemical outcomes involve analyzing transition states, identifying favored conformations, and determining approach selectivity based on steric interactions.
The document describes several reactions involving conjugate additions and discusses the stereochemical outcomes. It rationalizes the stereoselectivity using concepts like chair conformations, Felkin-Anh control, and Cram chelation control. By analyzing the transition states and preferred conformations, it is able to explain why the reactions favor one stereoisomer over another in each case.
This document summarizes the synthesis of the anti-cancer compound epothilone A. It discusses the retrosynthesis of epothilone C and the synthesis of the required fragments - C1-C6, C7-C12, and C13-C21. These fragments were coupled and the ring was formed using ring-closing metathesis. Finally, epothilone C was converted to the target compound epothilone A through oxidation and reduction reactions. The synthesis utilized substrate-controlled aldol reactions, Sharpless asymmetric dihydroxylation, and ring-closing metathesis to construct the molecule with high stereoselectivity.
An introduction to total synthesis and retrosynthesis. A quick overview of retrosynthesis followed by one of the many syntheses of (–)-stenine. This is just an overview of the fascinating world of organic synthesis, it is not intended to teach retrosynthesis or organic synthesis. For that see some of my other lecture notes.
Chiral catalysis. This is a relatively brief look at some classic examples of chiral catalysis in organic synthesis. It gives a quick overview but does not go into any detail.
The document discusses various topics related to chirality and stereochemistry including:
- Different forms that can exhibit chirality beyond just tetrahedral stereocenters.
- The relationship between enantiomers, diastereomers, and meso compounds for molecules with multiple stereocenters.
- How purity of chiral compounds is measured in terms of enantiomeric excess and ratio, and diastereomeric excess and ratio.
- Common methods for determining enantiomeric excess such as derivatization reactions and chiral chromatography.
These slides are part of a talk to school teachers. They were designed to showcase some of the applications of organic chemistry, the range of natural and synthetic products. I'm not sure how much use it is without my commentary but, as always, it seems a waste to leave it on my hard drive. The second half gave a overview of chirality and stereoisomers as this topic often causes problems with students. This second half owes a lot to an excellent paper by Robert Gawley (J. Chem. Ed. 2005, 82, 1009) and just has prettier papers. This version of the talk includes a section I removed when presenting (due to time) on artificial sweeteners.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
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.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
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.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
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.
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.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
2. Unit One
Parts 3&4
H O H3C Br O Br
H CH3
Locating electrons
Describing bonds Pages
Shape of molecules 34 & 43
3. Unit One
3&4
if we know where
Parts
electrons are we can
predict reactions and
shape...they really are
key to understanding
chemistry
H O H3C Br O Br
H CH3
Locating electrons
Describing bonds Pages
Shape of molecules 34 & 43
4. Unit One
Parts 3&4
H O H3C Br O Br
H CH3
as I’ve taken the
material out of order,
I’ll give you some
Locating electrons
page numbers
Describing bonds Pages
Shape of molecules 35 & 45
21. 1 18
1
H
H He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s1
energy
2s 2px 2py 2pz
hydrogen
Pg
1s 43
22. 1 18
1
H
H He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s1
energy
2s 2px 2py 2pz
just one electron
hydrogen
so in first orbital
Pg
1s 43
24. 1 18
2
H He
He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s2
energy
2s 2px 2py 2pz
helium
Pg
1s 43
25. 1 18
2
H He
He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s2
energy
2s 2px 2py 2pz
one electron has spin
+½ (up) and the other
spin –½ (down)
helium
Pg
1s 43
26. 1 18
2
H He
He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s2
energy
2s 2px 2py 2pz doesn’t matter what it
means...just remember
helium
an electron can only be
up or down
Pg
1s 43
27. 1 18
2
H He
He
2 13 14 15 16 17
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s2
energy
2s 2px 2py 2pz
so can only ever
have two electrons
per orbital helium
Pg
1s 43
28. 1 18
H He
2 13 14 15 16 17
3
Li Be B C N O F Ne
Li
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
2px 2py 2pz
1s22s1
energy
2s
lithium
Pg
1s 43
29. 1 18
H He
2 13 14 15 16 17
3
Li Be B C N O F Ne
Li
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
2px 2py 2pz
1s22s1
energy
lithium obeys both
rules...fill lowest orbital
2s first (until full) then fill
next lowest)
lithium
Pg
1s 43
30. 1 18
H He
2 13 14 15 16one more
...adding 17
4 electron is easy...
Li Be
Be B C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
2px 2py 2pz
1s22s2
energy
2s
beryllium
Pg
1s 43
31. 1 18
H He
2 13 14 15 16 17
5
Li Be B
B C N O F Ne
Na Mg ...and another... Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
2px 2py 2pz
1s22s22p1
energy
2s
boron
Pg
1s 43
32. 1 18
H He
2 13 14 15 16 17
5
Li Be B
B C N O F Ne
Na Mg it could go in any of
Al Si P S Cl Ar
3 4 5 6 7 8 9 10 x,11 y12 2pz,
2p 2p or
they’re identical...well
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn they are As Se Br Kr
energetically Ga Ge
2px 2py 2pz
1s22s22p1
energy
2s
boron
Pg
1s 43
33. 1 18
H He
2 13 14 15 16 17
5
Li Be B
B C N O F Ne
but, where does
Na Mg the next (and most Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
important as its
K Ca Sccarbon) go?? Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ti V Cr
2px 2py 2pz
1s22s22p1
energy
2s
boron
Pg
1s 43
34. Hund's rule
electrons as far apart as
possible
(de ge n er a t e o rb i tals)
(as long as it doesn’t
violate any of the
previous rules!)
35. Hund's rule
makes sense as like
charges always
repel...
electrons as far apart as
possible
(de ge n er a t e o rb i tals)
36. 1 18
H He
2 13 14 15 16 17
6
Li Be B C
C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s22s22p 12p 1
2px 2py 2pz
x y
energy
2s
1s22s22p2
carbon
Pg
1s 43
37. 1 18
H He
2 13 14 15 16 17
6
Li Be B C
C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s22s22p 12p 1
2px 2py 2pz could be 2pz,
makes no
x y
difference...
energy
2s
1s22s22p2
carbon
Pg
1s 43
38. that's a lot of
electrons...
luckily we don’t care
about all them...
40. 1 18
H He
2 13 14 15 16 17
6
Li Be B C
C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s22s22p2
carbon
atomic = number of
number electrons Pg
45
41. Valence electrons
1 18
H He
2 13 14 15 16 17
6
Li Be B C
C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
1s22s22p 12p 1
2px 2py 2pz
x y
energy
2s 1s22s22p2
carbon
Pg
1s
43
42. Valence electrons
1 18
H He
2 13 14 15 16 17
6
Li Be B C
C N O F Ne
Na Mg Al Si P S Cl Ar
3 4 5 6 7 8 9 10 11 12
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
only need consider high
energy electrons or those
on the outside called the
1s22s22p 12p 1
2px 2py 2pz valence electrons.
x y
energy
2s 1s22s22p2
carbon
Pg
1s
44
43. C C
if we consider the Bohr
model of the atom, the
1s22s22p2 atomwhere we thinkplanet 2
one
resembling a
of an
2s22p
with moons orbiting (or
the solar system)
N N
1s22s22p3 2s22p3
group 1 2 13 14 15 16 17 18
H He
Li Be B C N O F Ne Pg
44
44. C C
1s22s22p2 2s22p2
then the valence
electrons are those on the
outer edge (like Neptune
for young-upstarts or
Pluto for us oldies) N N
1s22s22p3 2s22p3
group 1 2 13 14 15 16 17 18
H He
Li Be B C N O F Ne Pg
44
45. C C
1s22s22p2 2s22p2
then the valence
electrons are those on the
outer edge (like Neptune
for young-upstarts or
Pluto for us oldies) N N
1s22s22p3 2s22p3
group 1 2 13 14 15 16 17 18
H He
Li Be B C N O F Ne Pg
44
46. C C
1s22s22p2 2s22p2
N N
1s22s22p3 2s22p3
absolute
rubbish...but more
group 1 2 13 14 15 16 17 18
comprehendible!
H He
Li Be B C N O F Ne Pg
41
47. C C
1s22s22p2 2s22p2
N N an easy we to
remember the number
of valence electrons is
1s22s22p3 2s22p3
to take group
number...
group 1 2 13 14 15 16 17 18
H He
Li Be B C N O F Ne Pg
41
48. C C
1s22s22p2 2s22p2
N N
...and ignore
1s22s22p3 2s22p3 first ‘1’
valence
electrons 1 2 3 4 5 6 7 8
H He
Li Be B C N O F Ne Pg
41
49. C C
1s22s22p2 2s22p2
N N
1s22s22p3 2s22p3
valence
electrons 1 2 3 4 5 6 7 8 so oxygen
(group 16) has
H He 6 valence
Li Be B C N O F Ne
electrons
Pg
41
66. C
1s22s22p2
4 bonds
hopefully, you can see
3
this is where those
magic numbers in
lecture one came
N bonds from!
1s22s22p3
O
1s22s22p4
2 bonds
Pg
34
67. Pg
8
36
H
H C H
H
Octet rule: 8 valence electrons
68. Pg
8
37/46
H H
H C N O
H H
Octet rule: 8 valence electrons
69. Pg
Lewis structures 37/46
Hydrofluoric acid HF
H + F H F ≡ H F
use octet rule to draw
Methanol CH OH
3
the structure of stable
molecules...
H H
C + O + 4H H C O H ≡H C O H
H H
70. Pg
Lewis structures 41
Hydrofluoric acid HF
H–F easy..H = 2
electrons (full s
orbital) & F = 8...
H + F H F ≡ H F
Methanol CH3OH
H H
C + O + 4H H C O H ≡H C O H
H H
71. Pg
Lewis structures 37/46
Lewis structure shows
all valence electrons
Hydrofluoric acid HF
represented by our
simple diagram H–F
H + F H F ≡ H F
Methanol CH3OH
H H
C + O + 4H H C O H ≡H C O H
H H
72. Pg
Lewis structures 37/46
Hydrofluoric acid HF
H + F H F ≡
works for
more complex
H F
molecules
Methanol CH3OH
H H
C + O + 4H H C O H ≡H C O H
H H
73. Pg
Lewis structures 37/46
Hydrofluoric acid HF
H + F H F ≡ H F
Methanol CH3OH
Note: it helps to leave
lone pairs (of electrons)
on diagram...this is
where a lot of chemistry
occurs... H
H
C + O + 4H H C O H ≡H C O H
H H
74. Acetone CH3COCH3
3 C + O + 6H
how do we deal
with more complex
molecules?
Pg
44
75. Acetone CH3COCH3
3 C + O + 6H
first draw all the
atoms where you think O
they might go...
H H
C
H C C H
H H
Pg
44
76. Acetone CH3COCH3
3 C + O + 6H
now join all the atoms
together...some of the
atoms have full
valence shells so we
can draw them in as on O
the next slide...
H C H
C C
H H
H H
Pg
44
77. Acetone CH3COCH3
3 C + O + 6H
the central C and O
both have only 7
valence electrons...
O
H C H
C C
H H
H H
Pg
44
78. Acetone CH3COCH3
3 C + O + 6H
O
...but if they share 4
electrons they both have H C H
8 valence electrons...this C C
gives us a double bond
H H
(alkene)
H H
O O
C
≡ Pg
H3C CH3 44
83. –
Borohydride
anion BH4 –
add electron
does it matter
which atom we give
the electron to?
H H
B + 3H + H H B H ≡ H B H
H H
Pg
44
84. –
Borohydride
anion BH4 –
add electron
does it matter
which atom we give
the electron to?
H H
B + 3H + H H B H ≡ H B
no! (but in this case
H
H H– makes more
H
chemical sense)
Pg
44
85. +
Ammonium
cation NH4 +
lose electron
if we have a
positive charge
(cation) we do
the opposite...
Pg
44
93. this is ‘electron book-
keeping’...we are just
assigning charge to one
atom to help explain
chemistry...
formal charges localise
charge on an atom...
94. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
...on an atom
Pg
47
95. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
...according to
the atoms
position in the
periodic table
Pg
47
96. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
...in lone pairs...
Pg
47
97. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
...or the number
of bonds to that
atom
Pg
47
98. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
H H
N + 3H + H H N H ≡ H N H
H H
cation
N fc = 5-0-½(8)=+1
Pg
47
99. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
H H
N + 3H + H H N H ≡ H N H
H H
no charge on H as:
cation
H = 1-0-½(2) = 0 N fc = 5-0-½(8)=+1
Pg
47
100. formal number of number of number of
charge = valence – unshared – bonds
(fc) electrons electrons
H H
the simplified
N + 3Hformula of bonds)
+ (just use
number
H H N H ≡ H N H
H H
cation
N fc = 5-0-4=+1
Pg
47
101. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
O3 neutral
ozone
Pg
47
102. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
O3 neutral
ozone
lhs O; fc = 6-4-½(4)=0
Pg
47
103. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
O3 neutral
ozone
lhs O; fc = 6-4-½(4)=0
central O; fc = 6-2-½(6)=+1
rhs O; fc = 6-6-½(2)=-1 Pg
47
104. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
O3 neutral
ozone
lhs O; fc = 6-4-½(4)=0
central O; fc = 6-2-½(6)=+1
rhs O; fc = 6-6-½(2)=-1 Pg
47
105. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
≡ O O
O
O3 neutral atom's formal
ozone charges
lhs O; fc = 6-4-½(4)=0
central O; fc = 6-2-½(6)=+1
rhs O; fc = 6-6-½(2)=-1 Pg
47
106. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
O
O + O + O
O O
O ≡ O
O
≡ O O
O
ozone neutral as
O3 neutral atom's formal
+ & – cancel each
ozone charges
other out
lhs O; fc = 6-4-½(4)=0
central O; fc = 6-2-½(6)=+1
rhs O; fc = 6-6-½(2)=-1 Pg
47
107. formal number of number of ½ number
charge = valence – unshared – of shared
(fc) electrons electrons electrons
these charges
explain why
ozone is so
reactive!
O
O + O + O
O O
O ≡ O
O
≡ O O
O
O3 neutral atom's formal
ozone charges
lhs O; fc = 6-4-½(4)=0
central O; fc = 6-2-½(6)=+1
rhs O; fc = 6-6-½(2)=-1 Pg
47
108. formal number of number of number of
charge = valence – unshared – bonds
(fc) electrons electrons
O
O + O + O
O O
O ≡ O
O
≡ O O
O
O3 neutral atom's formal
the simplified ozone charges
formula (just use
number of bonds)
lhs O; fc = 6-4-2=0
central O; fc = 6-2-3=+1
rhs O; fc = 6-6-1=-1 Pg
47
127. our simple Lewis model
helps explain a lot of
chemistry...especially
reactions... what is a
bond?
128. what is a
bond?
...but it fails to explain
such fundamental
concepts as shape...
129. ...actually, it can explain
shape if we use VSEPR
theory...but anyways,
lets use those orbitals
what is a
bond?
130. single (σ) bond
H• + H• H H
energy
here we have 2
hydrogen atoms
(each with 1 electron
in a 1s orbital)
Pg
H•
1s
H•
1s 37
131. single (σ) bond
H• + H• H H
σ*
to form a covalent
bond they must
energy
share their
electrons...
σ Pg
H•
1s
H–H H•
1s 35
132. single (σ) bond
H• + H• H H
σ*
energy
...this is achieved
by combining the
two atomic
Pg
orbitals to give...
σ
H•
1s
H–H H•
1s 35
133. single (σ) bond
H• + H• H H
σ* ...a new molecular
orbital, a sigma σ
orbital (or bond)
energy
σ Pg
H•
1s
H–H H•
1s 35
134. single (σ) bond
H• + H• H H
...this bonding
σ* orbital is lower in
energy than the
atoms...so a bond
will form
energy
σ Pg
H•
1s
H–H H•
1s 35
135. single (σ) bond
H• + H• H H
a consequence of the
maths is we also get an
anti-bonding sigma
orbital (σ*)...2 orbitals
σ*
must give 2 new orbitals
energy
σ Pg
H•
1s
H–H H•
1s 37
136. single (σ) bond
H• + H• H H
σ*
energy
...but lets ignore this
confusing little devil for
the time being!
σ Pg
H•
1s
H–H H•
1s 37
137. single (σ) bond
it is called a σ orbital as
is symmetrical along
bond axis (you can rotate
it like a cylinder and it
doesn’t change)
Pg
H H 47
138. single (σ) bond all bonds to H are
sigma (as all are like a
cylinder)...here we
overlap 1s of H with 2p
of C and get sigma
bond)
C• + H• C H
Pg
37
139. Pg
single (σ) bond 38
σ*
energy
if we take two 2p
orbitals and combine
them head-to-head
C• σ C•
2py C–C 2py
140. Pg
single (σ) bond 38
σ*
...we get a sigma
σ bonding
orbital...it is still
energy
like a cylinder...
C• σ C•
2py C–C 2py
141. Pg
single (σ) bond 38
σ*
energy
...this is the
normal single
bond we observe
in alkanes etc.
C• σ C•
2py C–C 2py
142. Pg
single (σ) bond 38
σ*
this is one orbital
NOT three
energy
C• σ C•
2py C–C 2py
143. single (σ) bond
the blue bit is the
sigma orbital...ignore
Pg
the red orbitals for
the time being...
35
144. single bond
or the simple
C C
version...
THIS IS ALL YOU
NEED TO KNOW
σ (sigma) bond
161. H3C CH3 CH3
CH3 CH3
the p bond prevents
O H
alkenes from rotating (the
two bonds can’t twist pass
multistep enzyme- each other)...
light isomerises
catalysed reverse complexed
process cis-retinal
H3C CH3 CH3 CH3 O
H
CH3
Pg
38
162. H3C CH3 CH3
CH3 CH3
this can effect
O H
shape of molecule
multistep enzyme- light isomerises
catalysed reverse complexed
process cis-retinal
H3C CH3 CH3 CH3 O
H
CH3
Pg
38
163. H3C CH3 CH3
CH3 CH3
O H
we must break π
bond before
multistep enzyme- light isomerises
catalysed reverse complexed alkene can rotate
process cis-retinal
H3C CH3 CH3 CH3 O
H
CH3
Pg
38
164. H3C CH3 CH3
CH3 CH3
the change in
O H
shape initiates the
visual cascade and
multistep enzyme- light isomerises our sight
catalysed reverse complexed
process cis-retinal
H3C CH3 CH3 CH3 O
H
CH3
Pg
38
165. H3C CH3 CH3
CH3 CH3
O H
multistep enzyme- light isomerises
catalysed reverse complexed
process cis-retinal
H3C CH3 CH3 CH3 O why do you think
red path is easy
H but blue hard?
CH3
Pg
38
166. double bond
or the simple
version...
THIS IS ALL YOU
NEED TO KNOW
π (pi) bond
168. sp2
an atom with three σ
orbitals and one π
orbital is called an sp2
atom (we only count the
C
orbitals used in making
Pg
s orbitals)
38
169. sp2 1
3
3
2
1 double bond and 2
single bonds and we
points have an sp2 atom
170. trigonal
planar
120°
sp2 atoms are trigonal planar
sp2
(flat and pointing to the
corners of a triangle)...again,
this is because the orbitals
Pg try to be as far apart as
possible
41
171. trigonal Pg
41
planar
sp 2
maximum separation of three points
maximum separation of three valence electron pairs
172. triple (σ + 2x π) bonds
σ
H C C H
π (2pz + 2pz) σ
a triple bond (like an π (2py + 2py)
alkyne) is formed from one
σ bond and two π bonds (at
right angles to each other
due to the direct of the p
orbitals that made them) σ π
H C C
π
H Pg
39
173. triple (σ + 2x π) bonds so...two p orbitals combine
head-to-head to give a σ bond
and two pairs of p orbitals
combine side-to-side to give
the two π orbitals (& there are
only two π orbitals)
σ
H C C H
π (2pz + 2pz) σ
π (2py + 2py)
σ π
H C C
π
H Pg
39
174. sp
an atom with two σ
orbitals and two π orbitals
is called an sp atom (as
two orbitals made the
basic σ skeleton)
C
Pg
39
178. H3C
H
CO2H
OH O
O
OCH3
H
here is a real
OH O molecule...we should be
dynemicin A able to identify the types
of atoms present...
Pg
40
179. four groups attached so
it must be sp3 and as
those groups try to stay
as far apart as possible
it is tetrahedral
H3C
H
CO2H
OH O
O
OCH3
H
OH O
dynemicin A
sp3
tetrahedral
Pg
40
180. ...only three groups so
sp2 and flat, trigonal
planar
H3C
H
CO2H
OH O
O sp2
OCH3 trigonal
H
planar
OH O
dynemicin A
sp3
tetrahedral
Pg
40
181. sp
linear
straight line, two
groups must be sp
H3C
H
and linear
CO2H
OH O
O sp2
OCH3 trigonal
H
planar
OH O
dynemicin A
sp3
tetrahedral
Pg
40
182. what is
oxygen?
H3C
H
CO2H
OH O
O
OCH3
H
OH O
dynemicin A
Pg
40
183. ...is it sp as
what is attached to two
oxygen? carbon atoms?
H3C
H
CO2H
OH O
O
OCH3
H
OH O
dynemicin A
Pg
40
184. sp, sp2 or sp3?
H
O look at a simpler
system...water, sp,
H sp2 or sp3?
185. sp, sp2 or sp3?
H
O H draw Lewis
structure...
186. sp, sp2 or sp3?
H
O H we have FOUR
groups around O,
two lone pairs &
two H atoms. So it
is...