2. tYPES oftYPES of
bondSbondS
1.1. Ionic bondIonic bond :Formed by transfer ofFormed by transfer of
electronselectrons
2.2. Covalent bond:Covalent bond: Formed by sharingormed by sharing
electronselectrons
3.3. Metallic bond:Metallic bond: Delocalization ofDelocalization of
electrons over large area of covalent bondelectrons over large area of covalent bond
3. IONic Bonding
• Electrons are transferred between
valence shells of atoms
• Ionic compounds are
made of ions
• Ionic compounds are called Salts or
Crystals
NOT MOLECULES
4. Covalent BondingCovalent Bonding
Covalent compounds form by sharing electrons
to attain a noble gas electron configuration
Regardless of the type of bond, the Octet Rule
still must be obeyed (8 valence electrons)
5. types of Covalent
Bonds
• Non Polar covalent bond:
This type of bond isThis type of bond is
formed when electrons areformed when electrons are
shared equally…shared equally…
• Polar covalent bond:
This type of bond isThis type of bond is
formed due to un equalformed due to un equal
6. .
Oxygen AtomOxygen Atom Oxygen AtomOxygen Atom
Oxygen Molecule (OOxygen Molecule (O22))
Non polar covalent bond – Equal
sharing of electrons
7. Other cases OfOther cases Of
cOvalent bOndcOvalent bOnd
• DOUBLE bond
– atoms that share two e- pairs (4 e-)
O O
• TRIPLE bond
– atoms that share three e- pairs (6
e-)
N N
8. Methane chMethane ch44
• This is the finished Lewis dotThis is the finished Lewis dot
structurestructure
How did we get here?How did we get here?
9. steps Or fOrMatiOnsteps Or fOrMatiOn
Of cOvalent bOndOf cOvalent bOnd
• Step 1
– count total valence e-
involved
• Step 2
– connect the central atom (usually the first in
the formula) to the others with single bonds
• Step 3
– complete valence shells of outer atoms
• Step 4
– add any extra e-
to central atom
IF the central atom has 8 valence e-
surrounding
it . . YOU’RE DONE!
10. Sometimes . . .
• You only have two atoms, so there is
no central atom, but follow the same
rules.
• Check & Share to make sure all the
atoms are “happy”.
Cl2 Br2 H2 O2 N2 HCl
11. ProPerties of
Molecular substances
Physical propertiesPhysical properties Covalent compoundsCovalent compounds
States (at room temperature)States (at room temperature) Liquid & gasLiquid & gas
Electrical conductivityElectrical conductivity Usually noneUsually none
Boiling point and Melting pointBoiling point and Melting point
Varies, but usually lower than ionicVaries, but usually lower than ionic
compoundscompounds
Solubility in waterSolubility in water
Varies, but usually lower than ionicVaries, but usually lower than ionic
compoundscompounds
Thermal conductivityThermal conductivity Usually lowUsually low
Covalent
bonding
