Bonding
Ionic – Metal/Non-metal
Cation/Anion
Cation: low ionization energy, lose
electrons
Anion: high ionization energy, gain
electrons
Lattice energy – Energy required to
separate a mole of solid ionic compound
into its ions(energy released when ionic
compound formed.)
L.E.=Q1Q2/r
Smaller radius-larger lattice energy
Higher charges-larger lattice energy
Covalent – Non-metals
Both have attraction for electronsorbitals overlap and electrons “share”
Polar: Uneven sharing – H2O, HCl
Dipole – slightly positive end and slightly
negative end
Larger difference in electronegativity
means larger dipole- more polar
Non-polar:
Even sharing – CO2, CH4, PH5, N2
Metallic Bonds – In metals
Free floating valence electrons that
surround positively charged metal ions.
Electrons are free to flow – conduct
electricity
Dot Structures: (Know)
O2, CO2, N2, F2, H2, CN-, C2H2, C2H4
Resonance Structures:
SO3
Measured bond lengths between S and O
are actually somewhere in between
length of a single and double bond.
Bond Length
Single bond-longer and weaker
Triple bond-shorter and stronger
Hybridization
-mixing atomic orbitals to form
molecular orbitals of equal energies.
Sigma + Pi Bonds
CH3COCHClCN
Intermolecular Forces –Between
molecules
Ionic
Hydrogen bonding H- F, O, N
Dipole-Dipole
Polar
London Dispersion
All types larger molecule = more London
forces
-London dispersion-Brief instants when
electron density greater on one side of
atom than the other.
- Temporary polarity (POLARIZABLE)
Stronger IMF…
B.P?
Surface tension?
Viscosity?
ΔHvap?
Vapor pressure?
Explain the Trend:
Compound
CH4
NH3
H2 O
BP (˚C)
-162
-33
100
Shapes/ Bond Angles
Vapor pressure (top of liquid)
Boiling
Vapor pressure is equal or greater than
the atmospheric pressure.
How can we make water boil at temps
less than 100˚C
High altitudes – water boils at lower
temperature (it takes longer to cook at
high altitude)
Pressure cooker - Boils at higher temps.
Molecular solids – Solids held together
by IMFs – NOT bonds
Ionic solids – Solids held together by
ionic bonds – salts
Covalent network solids – Covalent
bonded – large structures
graphite, diamond, quartz
Metallic solids – arranged in regularly
packed structures