CHEMICAL BONDS

  • The electrons that participated in this bonding are valence electrons.
  • Valence electrons are the outer shell electrons in an atom.
  • And an atomic symbol to represent th enuclues and inner electrons and dots (or crosses ) to represent the valence electrons are called Lewis Dot Symbol

INTRAMOLECULAR AND INTERMOLECULAR

click to edit

THE IONIC BOND AND COVALENT BOND

The Ionic Bond
Picture?

An ionic bond is electrostatic force of attraction between positive ion (cation) and negative ion ( anion) in an ionic compound

Ionic compound is made up of two oppositely charged ions (positive ion and negative ion) that held together through the transfer of electrons

The Covalent Bond. Picture?

The covalent bond is the sharing of one or more pairs of electrons by the bonded atoms in which each atom obtain octet confuguration

Types of covalent bond. Picture?

Single bond

  • Sharing of a pair of electrons by two atoms
  • Made up of a stigma bond

Double bond

  • Sharing of two pairs of electrons by two atoms
  • Made up of a sigma bond and a pi bond

Triple bond

  • Sharing of three pairs of electrons by two atoms
  • Made up of a stigma bond and two pi bond

Bond Polarity. Picture?

Non-polar

The distribution of electron density between the two bonded atoms is symmetrical

If the molecule made up of two atoms of same elements (similar electronegativity)

Polar

If the molecule made up of two atoms of different elements (different electronegativity)

The distribution of electron density between two bonded atoms is symmetrical

Intramolecular force(bonds)

  • hold together atoms in a molecule

Types of Intramolecular

Intermolecular Forces

  • The attractive forces that exist between molecules
  • Relatively weaker than intramolecular forces

They typically involve smaller charges which are farther apart

Their strength determines the physical properties (such as melting and boiling point) of the molecules

Types of intermolecular forces

Ion-Dipole Forces

  • Force of attraction between an ion and a polar molecule
    Picture?

Dipole-dipole force

  • attractions between opposite charges in polar molecules. Picture?

Hydrogen bonding ( a special type of dipole-dipole force)

London dispersion force (induced dipole-induced dipole force)

  • occurs between all molecules, but especially important in non-polar molecules because it is the only intermolecular force available for them
  • Example: (I2,H2,CH4,CH3CH2CH3) and noble gas like He, Ne, and Ar in very cold temperature.
  • Picture

Ionic bond

Non-polar covalent bond

Polar covalent bond

Lengths of Covalent Bonds. Picture?

Electronegativity

  • a measure of tendency of an atom to attract a pair of bonding pairs of electrons.Click for picture.