# 9.1 - Lewis Dot Symbols

* Chemists utilize Lewis dot symbols, a system of dots invented by Lewis, to keep track of valence electrons in a chemical process and ensure that the total number of electrons does not change.
  * A Lewis dot symbol is made up of the element's symbol plus one dot for each valence electron in the element's atom.

# 9.2 - The Ionic Bond

* Alkali metals and alkaline earth metals, on the other hand, are more likely to create cations in ionic compounds.
  * Halogens and oxygen are most likely to produce anions.
  * The electrostatic force that holds ions together in an ionic molecule is called an ionic bond.

# 9.3 - Lattice Energy of Ionic Compounds

* The total stability of a solid ionic compound is determined by interactions between all of these ions, not only between a single cation and a single anion. T
  * The lattice energy of an ionic solid is a quantitative indicator of its stability.
  * The energy required to completely separate one mole of a solid ionic compound into gaseous ions is known as lattice energy.
* Using Coulomb's law, we can determine the lattice energy of an ionic compound if we know its structure and composition.
  * Coulomb's law states that the potential energy (E) between two ions is proportional to the product of their charges and inversely proportional to their separation.
* By assuming that the creation of an ionic compound occurs in a series of steps, we can indirectly derive lattice energy.
  * The Born-Haber cycle connects the lattice energies of ionic compounds with ionization energies, electron affinities, and other atomic and molecular characteristics.

# 9.4 - The Covalent Bond

* A covalent bond is a bond between two atoms in which two electrons are shared.
  * Compounds with purely covalent bonding are known as covalent compounds.
* In the production of F2, just two valence electrons are involved.
  * The nonbonding electrons are referred to as lone pairs.
  * Lone pairs are valence electron pairs that are not involved in the creation of covalent bonds.
* Shared electron pairs are displayed as lines or pairs of dots between two atoms in a Lewis structure
  * While lone pairs are shown as pairs of dots on individual atoms.
* Lewis' octet rule is as follows: When an atom other than hydrogen is surrounded by eight valence electrons, it tends to form bonds.
* Different forms of covalent bonds can be formed by atoms.
  * One electron pair holds two atoms together in a single bond. Multiple bonds, or bonds created when two atoms share two or more pairs of electrons, hold many compounds together.
  * The covalent bond between two atoms is called a double bond when they share two pairs of electrons.
* Single covalent bonds are shorter than many ones.
  * The distance between the nuclei of two covalently bound atoms in a molecule is called bond length.

# 9.5 - Electronegativity

* Because electrons spend more time in the proximity of one atom than the other, a polar covalent bond, or simply a polar bond, is formed.
* Other polar bonds can be considered as a bridge between a (nonpolar) covalent link, in which electrons are shared evenly, and an ionic bond, in which electron(s) are transferred nearly completely.
  * Electronegativity, or an atom's propensity to draw the electrons in a chemical bond toward itself, is a feature that helps us identify a nonpolar covalent connection from a polar covalent link.

 ![Electronegativity](https://s3.amazonaws.com/knowt-user-attachments/images%2F1632786832329-1632786832329.png)

# 9.6 - Writing Lewis Structures

* Writing the compound's skeletal structure using chemical symbols and bound atoms adjacent to one another. This is a basic task for simple compounds.
  * We must either be given the knowledge or make an educated estimate for increasingly complex chemicals.
  * The middle position is usually occupied by the least electronegative element. In the Lewis structure, hydrogen and fluorine commonly occupy the terminal (end) sites.
* Count the total number of valence electrons present.
  * Add the number of negative charges to the total for polyatomic anions.
  * We add two electrons to a 2 ion because the 2 charge suggests that there are two more electrons available.
  * We remove the number of positive charges from this total for polyatomic cations.
* Connect the core atom to each of the surrounding atoms with a single covalent link. Complete the atoms bonded to the center atom's octets.
  * If electrons from the central or surrounding atoms are not involved in bonding, they must be shown as lone pairs.
  * Step 2 determines the total number of electrons that will be used.
* If the central atom has fewer than eight electrons after completing steps 1–3, try adding double electron-pair
  * Or triple bonds between the surrounding atoms and the central atom, completing the octet of the central atom with lone pairs from the surrounding atoms.

# 9.7 - Formal Charge and Lewis Structure

* We can determine the distribution of electrons in the molecule and draw the most feasible Lewis structure.
  * By comparing the number of electrons in an isolated atom with the number of electrons associated with the same atom in a Lewis structure.
  * The formal charge of an atom is the difference in electrical charge between its valence electrons and the number of electrons assigned to it in a Lewis structure.

# 9.8 - The Concept of Resonance

* The structures illustrated are resonance structures, as shown by the double-headed arrow.
  * As a result, a resonance structure is one of two or more Lewis structures for a single molecule that cannot be accurately represented by just one Lewis structure.
  * The term resonance refers to the representation of a specific molecule by two or more Lewis structures.

# 9.9 - Exceptions to the Octet Rule

* The BN bond in the above-mentioned chemical differs from the covalent bonds previously outlined in that the N atom contributes both electrons.
  * A coordinate covalent bond is one in which one of the atoms provides both electrons
  * It’s defined as a covalent link in which one of the atoms donates both electrons.

# 9.10 - Bond Enthalpy

* The enthalpy change required to break a specific bond in 1 mole of gaseous molecules is a measure of a molecule's stability.

 ![Bond Enthalpy](https://s3.amazonaws.com/knowt-user-attachments/images%2F1632786832749-1632786832749.png)

Chemistry

# 9.1 - Lewis Dot Symbols

* Chemists utilize Lewis dot symbols, a system of dots invented by Lewis, to keep track of valence electrons in a chemical process and ensure that the total number of electrons does not change.
  * A Lewis dot symbol is made up of the element's symbol plus one dot for each

Chapter 9 - Chemical Bonding I

Bryce Spann

View the note Chapter 9 - Chemical Bonding I: 9.1 - Lewis Dot SymbolsChemists utilize Lewis dot symbols, a system of dots invented by Lewis, to keep track of valence electrons in a chemical process and ensure that the total number of electrons does not change.A Lewis dot symbol is made up of the ele...