Ionic & Metallic Bonding

Chemical bonding that results from the electrical attraction between cations and anions

ELECTRONEGATIVITY DIFFERENCE SCALE

Ionic Compound – is composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal
Chemical formula shows the ratios of ions present
Formula unit – is the simplest collection of atoms from which an ionic compound’s formula can be established
Most are crystalline solids
Lattice energy – is the energy released when one mole of an ionic crystalline compound is formed from gaseous ions Gas to Solid
Lattice structure - Three dimensional arrangements vary depending upon the sizes and charges of the ions
Formation of ionic compounds is ALWAYS exothermic meaning energy is released
Cations-+ losses electrons
Anions- gains electrons (nonmetals)

Crystal Lattice

Chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons

Strong reflectors and absorbers of light due to many orbitals separated by extremely small energy differences
Metallic luster is due to re-radiated or reflected light
Malleable meaning they can be hammered or beaten into thin sheets
Ductile meaning they can be drawn, pulled or extruded through a small opening to produce a wire
Bond strength is determined by the metal’s enthalpy of vaporization (heat as energy required to vaporize substance)

Forces of attraction between molecules

Dipole-Dipole forces
equal but opposite charges that are separated by a short distance
The direction of the dipole is from the positive pole to the negative pole
Ex.

Something is more polar if it has a stronger electronegativity
Hydrogen Bonding
London Dispersion Forces
resulting from the constant motion of electrons and the creation of instantaneous dipoles
NOTE:
Act between all atoms and molecules
Only force that acts between noble gases and nonpolar molecules