Forces Between Particles
★ Static Electricity is caused by electric charges attracting or repelling each other
★ Repulsions and attractions are also known as electric forces, and these forces affect the properties of the substance
★ Ionic compounds have strong attractive forces that hold its ions together, which causes it to have a high melting and boiling points.
Uneven Molecular Charges
★ Polarity is a property of a system in which two points have opposite characteristics, such as charges or magnetic poles ( Polar and Non-Polar).
★ If the molecule is made up of 2 atoms, central atom has NO lone pairs of electrons, and all surrounding are the same then the molecule is Non- Polar.
★ If the molecule is made up of 2 atoms, EN difference ranges between 0.3 - 1.7, and violates all of the Non- polar rules then it is Polar .
Intramolecular Bonds
★ Connects atoms in a molecule (Ionic and Covalent)
★ Stronger that intermolecular forces
Intermolecular Bonds
★ Between 2 molecules
★ Attractive force between neighboring molecules
★ Types: Permanent dipole - dipole/ Hydrogen Bond/ Van de waals’
★ Weaker that covalent bonds
1. PERMENANT DIPOLE - DIPOLE
★ Polar + Polar NH2 + NH2
★ Occurs due to different electronegativity
★ Both are Dipoles that attract each other and from a permanent Dipole - Dipole bond.
2. HYDROGEN BONDS
★ Subtype of Permanent Dipole - Dipole
★ Bond between 𝝳 + H and either Nitrogen, Oxygen or Florine
★ Strongest intermolecular force
★ Strongest due to the strong attraction between 𝝳 + Hydrogen and lone pairs of electrons 𝝳- (Nitrogen, Oxygen or Fluorine).
★ Ex:- H20 + O2
3. VAN DER WALLS
★ Includes Dipole Induced Dipole force and London Dispersion.
★ Dipole Induced Dipole: A dipole makes a non- dipole momentarily a dipole EX: H2O + O2
★ Londen Dispersion: Non- Polar + Non- Polar EX: O2 + O2
Surface Tension
★ If the surface tension is high it doesn't spread
★ The attraction between molecules of the same substance is know as cohesion.
★ From strong to weak cohesion: Mercury, Water, Dimethyl sulfoxide and Acetone
★ The stronger the intramolecular the higher the boiling point and cohesion
★ When water freezes its density lessens Ice ⬆︎ density and Water ⬇︎ density
★ Density lessens because they lose kinetic energy and more bonds form.