Name ______________________
2.1 Notes: Atoms, Ions, & Molecules
Key Concept: All living things are based on atoms and their interactions.
Living things consist of different elements.
Atom: _________________________________________________________________________________
-Element: one type of atom
An atom has a nucleus and electrons.
-The nucleus contains __________________ and ___________________.
- An energy level is an _______________________________________________________________.
Compounds
-A compound is made of _____________________________________________________________.
-Examples: ________________________________________________________________________
Ions form when atoms gain or lose electrons.
-Positive ions: formed when atoms ______________________________________________________
-Negative ions: formed when atoms _____________________________________________________
Ionic bonds form ________________________________________________________________________
Covalent bonds form when ________________________________________________________________
-Molecule: ________________________________________________________________________
2.2 Notes: Properties of Water
Key Concept: Water’s unique properties allow life to exist on Earth.
Life depends on hydrogen bonds in water.
 Water is a ____________ molecule.
o Polar molecules: ______________________________________________________________
o Nonpolar molecules: __________________________________________________________
Hydrogen bonds are responsible for three important properties of water.
1. High specific heat: __________________________________________________________________
a. Example:
2. Cohesion: _________________________________________________________________________
a. Example:
3. Adhesion: _________________________________________________________________________
a. Example:
Solid ice is less dense than liquid water.
 Ice floats on water: one of the only solids to float on its liquid form – due to arrangement of water
molecules due to charged regions (water is polar).
o Provides insulation for water below (stays at about 4 degrees C – freezing point is 0 C)
Many compounds dissolve in water.
 A solution is formed when ___________________________________________________________.
A solution is a _____________________________________________.
 Parts of a solution (Ex. Salt water):
o Solvents ___________________________________________________________________
o Solutes _____________________________________________________________________
Polarity
 “Like dissolves like”
o Polar solvents dissolve polar solutes (Example: ______________________________________)
o Nonpolar solvents dissolve nonpolar solutes.
o Polar substances and nonpolar substances generally remain separate (think of ______________ forms a suspension when shaken).
Some compounds form acids or bases.
 Acids ____________________________________________________________________________
_________________________________________________________________________________
o pH: _____________________
 Neutral solutions ___________________________________________________________________
o pH: _____________________
 Bases ____________________________________________________________________________
_________________________________________________________________________________
o pH: _______________