Types of Chemical Bonds
Atoms with __________________ valence shells interact by either _________________
or_______________________ valence electrons.
__________________________: interactions that cause atoms to remain close together,
held by attractions
 The ____________ chemical bonds are covalent bonds and ionic bonds.
 _____________ bonds are considered ___________________________.
____________________: form when 2 or more atoms share valence electrons.
ex. CO2, _________, CH4, _________, 02

Sketch H2
 Oxygen needs to add ______ electrons to the 6 already present to ______________ its valence shell.
 Two oxygen atoms can form a molecule by sharing __________ pairs of valence electrons.
 These atoms have formed a _____________ covalent bond.
Atoms can also form ______________ covalent bonds.
Sketch O2
__________________________________: the attraction of an atom for the
electrons of a covalent bond
 Strongly electronegative atoms attempt to pull the shared electrons toward
themselves.
 Examples of highly electronegative atoms: ______________ and _____________
Polar Covalent Bond:
_________________________________- a molecule where the valence electrons
are being shared ______________________, creating __________________ and
_________________________ ends
 Because Oxygen is much more electronegative then hydrogen, the charge
of the ________________ becomes slightly ____________ and the
____________ becomes slightly _____________.
 examples or polar substances: __________, ____________, ___________
Polar
Molecule:
H2O
Sketch the
polar molecule:
H2O
Nonpolar Covalent bonds:
___________________________________________: A molecule where the
valence electrons are ________________________________.
In methane, because C and H do not differ much in electronegativity, they
________________________________.
 Examples of nonpolar substances: __________, fat, _______________
Another type of bond can form if two atoms are so unequal in their attraction for valence
electrons that one atom strips an electron completely from the other.
Ionic Bond
______________ in which one or more ___________________ from one atom are
removed and attached to another atom, resulting in _____________ and ____________
___________ which attract each other like ____________________.
 Bond is formed between ions with opposite charges. Ex. ______________
# p+ _____
# e- _____
= no charge
# p+ _____
# e- _____
= no charge
_________ chemical bonds also play a role in life
# p+ _____
# e- _____
= _______
charge
# p+ _____
# e- _____
= _______
charge
___________________________


A weak chemical attraction between polar molecules. Ex. H20
The partially positive charged hydrogen atom is attracted to partially negative
oxygen atom.
How Is Life Impacted? Properties of ______________

1.
2.
3.
4.
1.
Result of hydrogen bonding
_____________________
Ability to stabilize __________________
____________________ upon freezing
Versatile _____________________
_______________________________
 Attraction between molecules of the same kind.
 Water molecules bonded to other water molecules; hydrogen bond is cohesive
force
o Example: water beads
_______________________________
 Water molecules attracted to other polar substances
o ex. ____________(water vessels in trees), glass (meniscus)
__________________________: the elasticlike force that exists on the surface of a water
 some animals can stand, walk, or run on water without breaking the surface
2.
Water _______________________ air temperatures
 Water molecules bonded to other water molecules; hydrogen bond is cohesive
force
 Absorbs _____________ from air that is ____________, _____________heat to
air that is ___________________.
 Absorbs or releases a relatively large amount of heat with only a slight change in
temperature.
 Coastal areas have milder climates
 Stabilizes ___________________ temperatures
 Organisms resist changes in their own temperatures
Prevents terrestrial organisms from overheating
 Evaporation of water from _____________ cools tissues in leaves and keeps them
from becoming too warm in sunlight
 Evaporation of sweat from human skin? _________________________________
 Impact of humidity? ________________________________________________
3.
4.
Oceans and lakes don’t freeze solid because___________________________
 When a deep body of water cools, the floating ice _________________ the liquid
water below
 But, why does ice float? ______________________________________________
Water is the solvent of life
 Sea water and cells contain a great variety of dissolved ions
__________________________ - A mixture in which one or more substances are evenly
distributed in another substance.
 Because water is a polar molecule, ionic compounds and other polar molecules
can dissolve into it easily. ex. ___________ and _____________
 Non-polar molecules do not dissolve in water. ex. __________ and __________