Chemistry 9th class Chapter 1 Basic DefinitionsGhanwaSamad
This document provides definitions and explanations of fundamental chemistry concepts. It defines matter as anything that has mass and occupies space, and classifies matter as either a substance or mixture. A substance is a pure form of matter with fixed composition and properties, while a mixture contains two or more substances mixed together physically. Elements are substances made of only one type of atom that cannot be broken down further, while compounds are formed by chemical combination of two or more elements together in a fixed ratio to form new substances with different properties than the original elements. Mixtures can be separated into their original substances using physical methods, while compounds require chemical processes to break them down.
The document discusses electron configurations, which describe how electrons are distributed in atomic orbitals. It explains the Aufbau principle, which states that electrons fill lower energy orbitals first. The Pauli exclusion principle is described, stating that no more than two electrons can occupy any single orbital. Hund's rule is also covered, regarding the filling of degenerate orbitals. Examples are provided to illustrate these principles.
Chemical bonds form between atoms through electrostatic forces of attraction. There are strong covalent and ionic bonds that involve electron sharing or transfer, as well as weaker dipole-dipole and London dispersion forces. Covalent bonds form between nonmetals by sharing electron pairs, while ionic bonds form between metals and nonmetals through the transfer of electrons. The type and strength of bonding between atoms determines the properties of the resulting chemical substances.
Valence electrons are the outermost shell electrons of an atom that are involved in bonding. Elements in the same group on the periodic table have the same number of valence electrons because they exhibit similar chemical properties based on their valence electron configuration. Atoms seek to attain a full outer shell of 8 electrons to achieve stability through gaining, losing or sharing valence electrons in chemical bonds.
The document discusses chemical bonding and molecular structures. It explains that chemical bonding occurs through ionic bonding via the transfer of electrons between atoms, or covalent bonding via the sharing of electron pairs between atoms. It also describes molecular geometry models including VSEPR theory, which predicts the three-dimensional arrangements of atoms in molecules based on electron pair repulsion. Common molecular shapes such as linear, trigonal planar, tetrahedral and octahedral are defined.
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.
Chemistry 9th class Chapter 1 Basic DefinitionsGhanwaSamad
This document provides definitions and explanations of fundamental chemistry concepts. It defines matter as anything that has mass and occupies space, and classifies matter as either a substance or mixture. A substance is a pure form of matter with fixed composition and properties, while a mixture contains two or more substances mixed together physically. Elements are substances made of only one type of atom that cannot be broken down further, while compounds are formed by chemical combination of two or more elements together in a fixed ratio to form new substances with different properties than the original elements. Mixtures can be separated into their original substances using physical methods, while compounds require chemical processes to break them down.
The document discusses electron configurations, which describe how electrons are distributed in atomic orbitals. It explains the Aufbau principle, which states that electrons fill lower energy orbitals first. The Pauli exclusion principle is described, stating that no more than two electrons can occupy any single orbital. Hund's rule is also covered, regarding the filling of degenerate orbitals. Examples are provided to illustrate these principles.
Chemical bonds form between atoms through electrostatic forces of attraction. There are strong covalent and ionic bonds that involve electron sharing or transfer, as well as weaker dipole-dipole and London dispersion forces. Covalent bonds form between nonmetals by sharing electron pairs, while ionic bonds form between metals and nonmetals through the transfer of electrons. The type and strength of bonding between atoms determines the properties of the resulting chemical substances.
Valence electrons are the outermost shell electrons of an atom that are involved in bonding. Elements in the same group on the periodic table have the same number of valence electrons because they exhibit similar chemical properties based on their valence electron configuration. Atoms seek to attain a full outer shell of 8 electrons to achieve stability through gaining, losing or sharing valence electrons in chemical bonds.
The document discusses chemical bonding and molecular structures. It explains that chemical bonding occurs through ionic bonding via the transfer of electrons between atoms, or covalent bonding via the sharing of electron pairs between atoms. It also describes molecular geometry models including VSEPR theory, which predicts the three-dimensional arrangements of atoms in molecules based on electron pair repulsion. Common molecular shapes such as linear, trigonal planar, tetrahedral and octahedral are defined.
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 different types of chemical bonds:
1) Metallic bonds form when valence electrons are delocalized and shared between all metal atoms in a lattice, holding the positive ions together.
2) Ionic bonds form when a metal transfers electrons to a nonmetal, creating oppositely charged ions that are attracted to each other.
3) Covalent bonds form when two nonmetals share valence electrons in a molecule through electron pairs. Lewis structures are used to represent electron sharing in covalent bonds.
Electron affinity is the energy released when an electron is added to an isolated gaseous atom. Electron affinity increases with increasing atomic number and decreasing size, as effective nuclear charge increases. Electron affinity decreases with increasing size and number of electron shells, as effective nuclear charge decreases. Electron affinity also increases with greater effective nuclear charge and decreases with greater screening effects and stability of half or completely filled orbitals.
This document provides an overview of chemical bonding concepts including:
- The octet rule which states that main group elements form ions to achieve 8 valence electrons.
- Ionic and covalent bonds are formed through the transfer or sharing of electrons respectively.
- Lewis structures are used to represent electron pairing in molecules and predict molecular geometry based on electron pair repulsion.
This document discusses the development of atomic theory from Dalton's postulates to modern atomic structure. Some key points covered include:
- Dalton proposed atoms as the fundamental units of matter and that compounds are formed by combinations of atoms.
- Experiments by Thomson, Millikan, Rutherford and others led to the discovery of subatomic particles like electrons and the nuclear model of the atom.
- Isotopes were discovered, and the periodic table was developed to organize elements based on atomic structure.
- Ions, ionic bonds, and nomenclature of inorganic compounds and acids are also summarized.
This document provides an overview of molecular orbital theory. It explains that molecular orbital theory describes molecules in terms of orbitals and electron configurations similar to atomic orbital theory. The key points are:
- Molecular orbitals are formed from the overlapping of atomic orbitals on different atoms.
- Bonding orbitals are formed from constructive interference and lower the energy, while antibonding orbitals are formed from destructive interference and increase the energy.
- Homonuclear diatomic molecules like H2, O2, and N2 are discussed as examples, with their molecular orbitals, bond orders, and magnetic properties explained.
CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIESsarunkumar31
periodic table, modern periodic law, nomenclature of elements greater than 100,electronic configuration and types of elements,periodic trends in properties of elements.ionization enthalpy, effective nuclear charge, electronegativity, s, p d and f block elements, covalent radius, ionic radius, predicition of group, period and block, electron gain enthalpy, periodic trends and chemical reactivity
A molecule is defined as an electrically neutral group of at least two atoms held together by strong chemical bonds. Molecules can be made of a single element or different elements. The modern understanding of molecules evolved from early theories proposed by scientists like Dalton, Avogadro, and Cannizaro in the 19th century. A key concept is that equal volumes of gases contain equal numbers of molecules. Molecules have a definite mass and structure that determines their properties.
This document provides an overview of chemical bonding concepts including the four main types of bonds (ionic, covalent, metallic, and polar covalent) and their properties. It also discusses electronegativity and bond polarity, Lewis structures, the octet rule, valence shell electron pair repulsion theory (VSEPR) and molecular geometry. Hybridization of orbitals is explained using examples of sp, sp2, and sp3 hybridization. The document concludes by noting some exceptions and limitations of the valence bond theory for more complex molecules and transition metals.
- The mole concept allows chemists to conveniently keep track of large numbers of particles. A mole is defined as 6.02 x 1023 particles, whether atoms, molecules, ions, etc.
- The formula mass (or molar mass) of a compound is the sum of the atomic masses of each element in its chemical formula. It has units of grams per mole (g/mol).
- Calculations involving moles, mass, particles and formula mass allow conversions between the microscopic and macroscopic scales in chemistry.
The document discusses chemical equilibrium, including:
- When equilibrium is reached, concentrations of reactants and products remain constant, with the forward and reverse reaction rates being equal.
- Le Chatelier's principle states that applying stress (changing temperature, concentration, volume, or pressure) causes a system at equilibrium to shift in a way that reduces the stress.
- For example, increasing temperature shifts exothermic reactions toward reactants and endothermic reactions toward products.
The attractive force which holds various constituents (atom, ions, etc.) together and stabilizes them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between its constituents; The stronger the bonding between the constituents, the more stable the resulting compound would be.
The document discusses the determination of lattice energy of ionic compounds using the Born-Haber cycle. It explains that the lattice energy of sodium chloride can be determined experimentally by considering its formation through two different methods. Method 1 is the direct combination of solid sodium and gaseous chlorine to form solid sodium chloride. Method 2 involves 5 steps including sublimation, dissociation, ionization, and combining to form ions and the ionic solid. Using Hess's law, the lattice energy is calculated by equating the enthalpy change between the two methods. For sodium chloride, the calculated lattice energy is -773.95 kJ/mol.
VSEPR (Valence Shell Electron Pair Repulsion) theory predicts molecular geometry based on the repulsion of electron pairs in the valence shell of an atom. It states that electron pairs will adopt a geometry that minimizes repulsion by maximizing distance between electron pairs. The number and type of electron pairs (lone pairs or bond pairs) determines the molecular shape. Lone pairs occupy more space than bond pairs due to greater repulsion from the single nucleus. Molecular geometry can be distorted from ideal shapes by the presence of lone pairs.
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.
Chemical bonding can occur through either ionic bonds or covalent bonds. Ionic bonds result from the electrostatic attraction between oppositely charged ions, while covalent bonds form through the sharing of electrons between atoms. The strength of these bonds can vary considerably, from strong primary bonds to weaker secondary bonds.
This document discusses the three main types of chemical bonds: ionic, covalent, and metallic. Ionic bonds form between metals and nonmetals when the metal transfers electrons to the nonmetal. Covalent bonds form when atoms share electrons in either single, double or triple bonds. Metallic bonds form when metal atoms contribute electrons to form a "sea of electrons" that are shared between all the atoms.
Organic chemistry revision notes cover the formation of fossil fuels like oil from dead marine organisms under heat and pressure. Crude oil is separated into fractions like gasoline and kerosene through fractional distillation, and combustion produces pollution like carbon monoxide and nitrogen oxides. The energy released during combustion can be measured using a calorimeter. Homologous series are families of compounds with the same functional group and general formula that differ by CH2. Main series include alkanes, alkenes, and alcohols, which are named based on their carbon chain and functional group.
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.
Class 11 Chapter 4 Chemical Bonding and Molecular Structure.pptxRajnishPrasadSarma
This document provides an overview of chemical bonding and molecular structure. It discusses topics such as octet rule, covalent bonds, limitations of the octet rule, ionic or electrovalent bonds, lattice enthalpy, bond parameters including bond length, bond angle, bond enthalpy and bond order. It also covers concepts of resonance, polar covalent bonds, dipole moment and covalent character in ionic bonds based on Fajans' rule. The document is presented as part of a Class XI chemistry curriculum on this unit.
Lewis structures show the bonding between atoms in a molecule using dots to represent valence electrons. The octet rule states that atoms are most stable when their valence shells are filled with eight electrons. Valence shell electron pair repulsion (VSEPR) theory predicts molecular geometry based on minimizing electron pair repulsion around a central atom. VSEPR identifies five basic molecular geometries (linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral) depending on the number of electron pairs around the central atom. Lone pairs influence molecular geometry differently than bonding pairs.
This document discusses different types of chemical bonds:
1) Metallic bonds form when valence electrons are delocalized and shared between all metal atoms in a lattice, holding the positive ions together.
2) Ionic bonds form when a metal transfers electrons to a nonmetal, creating oppositely charged ions that are attracted to each other.
3) Covalent bonds form when two nonmetals share valence electrons in a molecule through electron pairs. Lewis structures are used to represent electron sharing in covalent bonds.
Electron affinity is the energy released when an electron is added to an isolated gaseous atom. Electron affinity increases with increasing atomic number and decreasing size, as effective nuclear charge increases. Electron affinity decreases with increasing size and number of electron shells, as effective nuclear charge decreases. Electron affinity also increases with greater effective nuclear charge and decreases with greater screening effects and stability of half or completely filled orbitals.
This document provides an overview of chemical bonding concepts including:
- The octet rule which states that main group elements form ions to achieve 8 valence electrons.
- Ionic and covalent bonds are formed through the transfer or sharing of electrons respectively.
- Lewis structures are used to represent electron pairing in molecules and predict molecular geometry based on electron pair repulsion.
This document discusses the development of atomic theory from Dalton's postulates to modern atomic structure. Some key points covered include:
- Dalton proposed atoms as the fundamental units of matter and that compounds are formed by combinations of atoms.
- Experiments by Thomson, Millikan, Rutherford and others led to the discovery of subatomic particles like electrons and the nuclear model of the atom.
- Isotopes were discovered, and the periodic table was developed to organize elements based on atomic structure.
- Ions, ionic bonds, and nomenclature of inorganic compounds and acids are also summarized.
This document provides an overview of molecular orbital theory. It explains that molecular orbital theory describes molecules in terms of orbitals and electron configurations similar to atomic orbital theory. The key points are:
- Molecular orbitals are formed from the overlapping of atomic orbitals on different atoms.
- Bonding orbitals are formed from constructive interference and lower the energy, while antibonding orbitals are formed from destructive interference and increase the energy.
- Homonuclear diatomic molecules like H2, O2, and N2 are discussed as examples, with their molecular orbitals, bond orders, and magnetic properties explained.
CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIESsarunkumar31
periodic table, modern periodic law, nomenclature of elements greater than 100,electronic configuration and types of elements,periodic trends in properties of elements.ionization enthalpy, effective nuclear charge, electronegativity, s, p d and f block elements, covalent radius, ionic radius, predicition of group, period and block, electron gain enthalpy, periodic trends and chemical reactivity
A molecule is defined as an electrically neutral group of at least two atoms held together by strong chemical bonds. Molecules can be made of a single element or different elements. The modern understanding of molecules evolved from early theories proposed by scientists like Dalton, Avogadro, and Cannizaro in the 19th century. A key concept is that equal volumes of gases contain equal numbers of molecules. Molecules have a definite mass and structure that determines their properties.
This document provides an overview of chemical bonding concepts including the four main types of bonds (ionic, covalent, metallic, and polar covalent) and their properties. It also discusses electronegativity and bond polarity, Lewis structures, the octet rule, valence shell electron pair repulsion theory (VSEPR) and molecular geometry. Hybridization of orbitals is explained using examples of sp, sp2, and sp3 hybridization. The document concludes by noting some exceptions and limitations of the valence bond theory for more complex molecules and transition metals.
- The mole concept allows chemists to conveniently keep track of large numbers of particles. A mole is defined as 6.02 x 1023 particles, whether atoms, molecules, ions, etc.
- The formula mass (or molar mass) of a compound is the sum of the atomic masses of each element in its chemical formula. It has units of grams per mole (g/mol).
- Calculations involving moles, mass, particles and formula mass allow conversions between the microscopic and macroscopic scales in chemistry.
The document discusses chemical equilibrium, including:
- When equilibrium is reached, concentrations of reactants and products remain constant, with the forward and reverse reaction rates being equal.
- Le Chatelier's principle states that applying stress (changing temperature, concentration, volume, or pressure) causes a system at equilibrium to shift in a way that reduces the stress.
- For example, increasing temperature shifts exothermic reactions toward reactants and endothermic reactions toward products.
The attractive force which holds various constituents (atom, ions, etc.) together and stabilizes them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between its constituents; The stronger the bonding between the constituents, the more stable the resulting compound would be.
The document discusses the determination of lattice energy of ionic compounds using the Born-Haber cycle. It explains that the lattice energy of sodium chloride can be determined experimentally by considering its formation through two different methods. Method 1 is the direct combination of solid sodium and gaseous chlorine to form solid sodium chloride. Method 2 involves 5 steps including sublimation, dissociation, ionization, and combining to form ions and the ionic solid. Using Hess's law, the lattice energy is calculated by equating the enthalpy change between the two methods. For sodium chloride, the calculated lattice energy is -773.95 kJ/mol.
VSEPR (Valence Shell Electron Pair Repulsion) theory predicts molecular geometry based on the repulsion of electron pairs in the valence shell of an atom. It states that electron pairs will adopt a geometry that minimizes repulsion by maximizing distance between electron pairs. The number and type of electron pairs (lone pairs or bond pairs) determines the molecular shape. Lone pairs occupy more space than bond pairs due to greater repulsion from the single nucleus. Molecular geometry can be distorted from ideal shapes by the presence of lone pairs.
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.
Chemical bonding can occur through either ionic bonds or covalent bonds. Ionic bonds result from the electrostatic attraction between oppositely charged ions, while covalent bonds form through the sharing of electrons between atoms. The strength of these bonds can vary considerably, from strong primary bonds to weaker secondary bonds.
This document discusses the three main types of chemical bonds: ionic, covalent, and metallic. Ionic bonds form between metals and nonmetals when the metal transfers electrons to the nonmetal. Covalent bonds form when atoms share electrons in either single, double or triple bonds. Metallic bonds form when metal atoms contribute electrons to form a "sea of electrons" that are shared between all the atoms.
Organic chemistry revision notes cover the formation of fossil fuels like oil from dead marine organisms under heat and pressure. Crude oil is separated into fractions like gasoline and kerosene through fractional distillation, and combustion produces pollution like carbon monoxide and nitrogen oxides. The energy released during combustion can be measured using a calorimeter. Homologous series are families of compounds with the same functional group and general formula that differ by CH2. Main series include alkanes, alkenes, and alcohols, which are named based on their carbon chain and functional group.
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.
Class 11 Chapter 4 Chemical Bonding and Molecular Structure.pptxRajnishPrasadSarma
This document provides an overview of chemical bonding and molecular structure. It discusses topics such as octet rule, covalent bonds, limitations of the octet rule, ionic or electrovalent bonds, lattice enthalpy, bond parameters including bond length, bond angle, bond enthalpy and bond order. It also covers concepts of resonance, polar covalent bonds, dipole moment and covalent character in ionic bonds based on Fajans' rule. The document is presented as part of a Class XI chemistry curriculum on this unit.
Lewis structures show the bonding between atoms in a molecule using dots to represent valence electrons. The octet rule states that atoms are most stable when their valence shells are filled with eight electrons. Valence shell electron pair repulsion (VSEPR) theory predicts molecular geometry based on minimizing electron pair repulsion around a central atom. VSEPR identifies five basic molecular geometries (linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral) depending on the number of electron pairs around the central atom. Lone pairs influence molecular geometry differently than bonding pairs.
Lewis and Kossel were the first to successfully explain chemical bonding in terms of electrons. They proposed that atoms bond to achieve stable electron configurations like noble gases. Lewis pictured atoms as a positively charged nucleus surrounded by 8 electrons. Atoms bond by transferring or sharing electrons to achieve stable octets. Lewis symbols were introduced to represent valence electrons. Covalent bonds form when atoms share valence electrons in order to gain full outer shells. Resonance structures represent situations where no single Lewis structure adequately describes the molecule.
CH 4 CHEMICAL BONDING AND MOLECULAR STRUCTURE 3.pdfLUXMIKANTGIRI
Lewis and Kossel were the first to successfully explain chemical bonding in terms of electrons. They proposed that atoms bond to achieve stable electron configurations like noble gases. Lewis pictured atoms as a positively charged nucleus surrounded by 8 electrons. He proposed that atoms bond by transferring or sharing electrons to achieve stable octets. Lewis symbols were introduced to represent valence electrons. Covalent bonds form when atoms share valence electrons to achieve stable octets. Resonance structures represent situations where no single Lewis structure adequately describes the molecule.
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
chap8lect_2015, perteneciente a fiisca del estado solido.pptJorgespw
The document summarizes key concepts in chemical bonding, including the three main types of bonds (ionic, covalent, and metallic), ionic bonding between metals and nonmetals, energetics of ionic bonding involving ionization energy, electron affinity, and lattice energy, properties of covalent bonding including polar covalent bonds and electronegativity, Lewis structures for representing covalent bonding including exceptions to the octet rule, and resonance structures.
This document provides an overview of chemical bonding concepts including ionic bonds, covalent bonds, electronegativity, and molecular shapes. Key points covered include: 1) Ionic bonds form between cations and anions via electrostatic attraction while covalent bonds form through the sharing of electron pairs. 2) Electronegativity determines the polarity of covalent bonds, with more electronegative atoms attracting bonding electrons. 3) VSEPR theory predicts molecular geometry based on electron pair-atom repulsion.
chemical bonding and molecular structure class 11sarunkumar31
hybridisation, bonding and antiboding, dipole moment, VSPER theory, Molecular orbital diagram, Phosphorous pentachloride, ionic bond, bond order, bond enthalpy, bond dissociation, sp and sp2hybridisation, hydrogen bonding,electron pair,lone pair repulsion, resonance structure of ozone, how to find electron pair and lone pair, sp3 hybridization of methane.
Chemical bonding xi , dr.mona srivastava , founder masterchemclassesDR MONA Srivastava
Viewers,
This ppt of chemical bonding is designed to give a complete idea and though conceptual extract of the topic for the students of XI to help them understand the basics of chemical bonding in chemistry. Hope it covers all important aspects and points .
Dr Mona Srivastava
Founder-
Masterchemclasses
This document discusses different types of chemical bonds including ionic, covalent, and metallic bonds. It describes the formation of ionic bonds between metals and nonmetals and how ionization energy, electron affinity, and lattice energy contribute to the energetics of ionic bonding. Covalent bonding is explained as the sharing of electrons between nonmetals. Factors that determine bond polarity like electronegativity are also covered. The document provides details on writing Lewis structures, accounting for valence electrons and formal charges. Exceptions to the octet rule for molecules with odd numbers of electrons, incomplete octets, and expanded octets are explained.
Covalent bonds form between nonmetal atoms by sharing valence electrons. Atoms share electrons to attain stable electron configurations like noble gases. Lewis structures show how valence electrons are arranged between bonded atoms. To draw Lewis structures, count the total valence electrons and distribute them to form single or double bonds between atoms until each atom has an octet of electrons. Examples of molecules held by covalent bonds are hydrogen, oxygen, and chlorine.
This document discusses different types of chemical bonds including ionic, covalent, and metallic bonds. It describes the concepts of electronegativity, resonance structures, and exceptions to the octet rule. Bond strength is quantified by bond enthalpy, which is the energy required to break a bond. Stronger bonds have higher bond enthalpies and shorter bond lengths.
The attractive force which holds various constituents (atom, ions, etc.) together and stabilizes them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between its constituents; The stronger the bonding between the constituents, the more stable the resulting compound would be.
This document discusses covalent compounds and their formation through shared electron pairs between nonmetals. It covers the octet rule for achieving stable electron configurations, different types of covalent bonds, and how to draw Lewis structures by arranging electrons around atoms. Exceptions to the octet rule are presented. Guidelines for naming covalent compounds from their formulas and writing formulas from names are also provided, along with examples.
1). Chemical bonds form when atoms gain, lose, or share electrons to achieve stable noble gas configurations. Ionic bonds occur through electron transfer between metals and nonmetals, while covalent bonds form through electron sharing.
2). Lewis dot structures use dots to represent valence electrons and illustrate octet formations. Exceptions include expanded and incomplete octets. Molecular geometry is determined by minimizing electron pair repulsion using the VSEPR model.
3). Bond properties like length, energy, order, and angle are influenced by bonding type. Ionic compounds maximize lattice energy through opposite ion arrangements.
1). Chemical bonds form when atoms gain, lose, or share electrons to achieve stable electron configurations like the noble gas configuration. Lewis dot structures use dots to represent valence electrons and show electron sharing between atoms.
2). Ionic bonds form when a metal transfers an electron to a nonmetal, creating oppositely charged ions that are attracted to each other. Covalent bonds form when atoms share one or more pairs of electrons to achieve stable octets.
3). The VSEPR theory predicts molecular geometry based on electron pair-pair repulsion, treating bond pairs and lone pairs as electron domains around a central atom that arrange to maximize distance between each other. Common molecular geometries include linear, trigonal planar,
This document discusses chemical bonding and molecular structure. It begins by explaining that atoms combine through chemical bonds to form molecules and different theories have sought to explain why certain combinations are possible and what determines molecular shapes. It then summarizes Kössel-Lewis approach to chemical bonding, which proposed that atoms achieve stability by gaining or sharing electrons to attain a full outer shell of 8 electrons. Covalent bonds are formed by shared pairs of electrons between atoms. Lewis structures use dots to represent valence electrons and predict molecular geometry.
This document provides an overview of chemical bonding, including ionic and covalent bonds. It explains that ionic bonds form when ions transfer electrons, while covalent bonds form when atoms share electrons. The octet rule and Lewis electron dot diagrams are introduced to show how atoms gain or share electrons to achieve stable electron configurations like noble gases. Ionic compounds are formed from metals transferring electrons to nonmetals, resulting in cations and anions that bond ionically. Covalent compounds are formed by nonmetals sharing electrons in molecules. Molecular geometry is also discussed, including the shapes of molecules based on the number of electron pairs around the central atom.
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Coordination compounds (12th Maharashtra state board)Freya Cardozo
As per revised textbook 2019-2020. Ligands, Werners theory, Valence bond theory, Crystal field splitting theory, Application of coordination compounds, IUPAC
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The document discusses the structure of the atom and the discovery of subatomic particles like electrons, protons, and neutrons. It describes experiments done by scientists like J.J. Thompson, Ernest Rutherford, and James Chadwick that led to the discovery of these fundamental particles. Key findings include the discovery of electrons as negatively charged particles in cathode rays, Rutherford's discovery of the nucleus through alpha particle scattering experiments, and Chadwick's discovery of the neutron through experiments with beryllium radiation.
Ionic equilibrium chapter 3(12th HSC Maharashtra state board)Freya Cardozo
The document discusses ionic equilibrium and acid-base theories. It provides examples of different types of salts based on the strength of acids and bases involved:
1) Salts of strong acids and bases, like NaCl, are neutral as they do not undergo hydrolysis.
2) Salts of strong acids and weak bases, like CuSO4, are acidic due to hydrolysis of the metal cation.
3) Salts of weak acids and strong bases, like CH3COONa, are basic due to hydrolysis of the anion.
4) Salts of weak acids and weak bases can be acidic, basic or neutral depending on whether the Ka or Kb is greater and the extent of hydro
Biological membranes as a barriers to drugs(pH trapping)Freya Cardozo
Transport of drugs across the membrane, Passive Diffusion, carrier mediated, Facilitated, Endocytosis, Ion transport and pH trapping.
Blood brain barrier and(BBB) stratergies to overcome BBB
Solid state 12th Maharashtra state boardFreya Cardozo
- Solids can be crystalline or amorphous. Crystalline solids have long-range order while amorphous solids have short-range order.
- There are four main types of crystalline solids: ionic, molecular, metallic, and covalent networks. They differ in the type of particles that make them up and the nature of bonding between the particles.
- Crystalline solids can form different crystal structures depending on how the particles are packed together in the lattice. Common structures include simple cubic, body-centered cubic, and face-centered cubic.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
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When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
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As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
2. KÖSSEL-LEWIS
APPROACH
TO CHEMICAL
BONDING
Lewis pictured the atom in terms of a
positively charged ‘Kernel’ (the nucleus plus
the inner electrons) and the outer shell that
could accommodate a maximum of eight
electrons
This octet of electrons, represents a
particularly stable electronic arrangement.
Lewis postulated that atoms achieve the
stable octet when they are linked by
chemical bonds.
E.g. F2, O2 etc
3. Lewis symbol
• outer shell electrons take part in chemical combination and they are known
as valence electrons.
• The inner shell electrons are well protected and are generally not involved in
the combination process.
• Thus to represent the valence elcetrons lewis developed an representation
method called the Lewis symbol
4. Significance
• This number of valence electrons helps to calculate the common or group valence of the
element.
• The group valence of the elements is generally either equal to the number of dots in Lewis
symbols or 8 minus the number of dots or valence electrons.
• E.g. Na has 7e- in valence shell so valency is 1
5. Kossel- Lewis
• First time explained a type of bond that is the electrovalent/ionic bond
• They explained how the highly electropositive Grp 1 elements bond with the
group 17 electronegative elements.
• They bond in order to achieve the stable noble gas configuration
• The duplet or octet state in their valence orbitals.
• Thus the bonding formed in order to achieve it is called electrovalent bond
• The electrovalence is thus equal to the number of unit charge(s) on the ion
6. Octet rule
Kössel and Lewis in 1916 developed an important theory of chemical
combination between atoms known as electronic theory of chemical
bonding.
According to this, atoms can combine either by transfer of valence
electrons from one atom to another (gaining or losing) or by sharing of
valence electrons in order to have an octet in their valence shells. This
is known as octet rule
7. Langmuir’s theory of Covalent bond
• Each bond is formed as a result of sharing of an electron pair between
the atoms.
• Each combining atom contributes at least one electron to the shared
pair.
• The combining atoms attain the outershell noble gas configurations
as a result of the sharing of electrons
E.g. Formation of Cl2
8. • If two atoms share two pairs of electrons, the covalent bond
between them is called a double bond. For example, in the carbon
dioxide molecule
• When combining atoms share three electron pairs as in the case of
two nitrogen atoms in the N2 molecule and the two carbon atoms in
the ethyne molecule, a triple bond is formed
9. Rules to write Lewis structure – E.g.
CO32-
1. Write the symmetrical skeleton for the polyatomic ions
O C O 2- C1s22s22p2 O1s22s22p4
O
2. Calculate the number of electrons available in the valence shell of all atoms (A)
A= 1x4(C)+3x6(O)+2(for extra 2 e-)=24 e-
3. Calculate the total number of electrons needed by atoms to accqire the noble gas config(N)
N=1x8+3x8=32 e-
4. Calculate total number of electrons shared(S) i.e S=N-A
S=32-24=8 e- i.e 8/2=4 pairs of electrons
10. 5. Place the shared electrons in the skeleton.
Use = and triple bonds wherever necessary
[O:C::O]2-
..
O
11. E.g. Ozone(O3)
1. Skeleton - O1s22s22p4
O
O O
2. Calculate A
A=3x6=18e-
3. Calculate N
N=3x8=24e-
4. S=N-A=24-18=6e- i.e 6/2=3 electron pairs
12. Bond order
• Bond Order is given by the number of
bonds between the two atoms in a
molecule
• Isoelectronic molecules and ions have
identical bond orders; for example, F2
and O2 have bond order 1.
• N2 , CO and NO+ have bond order 3
13. Formal charge
• The formal charge of an atom in a polyatomic molecule or ion may be defined as the
difference between the number of valence electrons of that atom in an isolated or
free state and the number of electrons assigned to that atom in the Lewis structure
• Formal charge (F.C.) on an atom in a Lewis structure =
total number of valence electrons in the free atom
— total number of non bonding (lone pair) electrons
— (1/2) total number of bonding(shared) electrons
• F.C = VE-LP-1/2 x BE
16. Significance of formal charge
• It helps to calculate the charge on the atoms in a Lewis structure
• It helps to calculate the number of valence electrons
• Formal charges help in the selection of the lowest energy structure
from a number of possible Lewis structures for a given species
18. Incomplete
octet
• In some compounds, the
number of electrons
surrounding the central atom
is less than eight. This is
especially the case with
elements having less than
four valence electrons.
Examples are LiCl, BeH2 and
BCl3
19. 2. Odd electron
molecules
In molecules with an odd
number of electrons like nitric
oxide, NO and nitrogen dioxide,
NO2 , the octet rule is not
satisfied for all the atoms
20. 3. Expanded octet
• Elements in and beyond the third period of the periodic table
have, apart from 3s and 3p orbitals, 3d orbitals also available for
bonding.
• In a number of compounds of these elements there are more than
eight valence electrons around the central atom
• examples of such compounds are: PF5 , SF6 , H2SO4 and a number
of coordination compounds.
21. Other drawbacks
• It is clear that octet rule is based upon the chemical inertness of
noble gases. However, some noble gases (for example xenon and
krypton) also combine with oxygen and fluorine to form a number of
compounds like XeF2 , KrF2 , XeOF2 etc.,
• This theory does not account for the shape of molecules.
• It does not explain the relative stability of the molecules being totally
silent about the energy of a molecule.