1. Properties of Matter,
Elements, Compounds,
and Bonding.
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2. Chemical Properties.
A chemical change pemanantly changes the conpound
into another.
Basic unit of matter is an atom
Subatomic particles- protons (+), neutrons, and electrons
(-)

3. Atoms
Protons neutrons in the nucleus
Electrons travel around the nucleus in orbits or clouds or
levels of energy.
Atom is neither positive or negative in charge - it is
neutral.
ION- An atom that has lost or gained an electron(s)

4. Identifying Elements
Atomic number- number of protons
The number of protons (atomic number) determines the
identity of an element
An element- only one type of atom
Represented by a chemical symbol such as O for oxygen
or Na for sodium
CHNOPS- Carbon, Hydrogen, Nitrogen, Oxygen,
Phosphorous, Sodium  main elements of human body

5. Isotopes
Atoms of the same element that have a different number
of neutrons
Many (not all) are unstable and break down, emitting
energy – radioactive isotopes
Used for determining the age of fossils, treatment of
diseases, and even to sterilize food.

6. Chemical Compounds
Compounds- Chemical combination of
two or more elements
 Represented by a chemical formula that
indicated the elements in the compound
and their proportions.

7. Chemical Bonding
In order to become stable, an atom will either gain, lose,
or share electrons. Each level can hold only a certain
number of electrons. (2,8,8)
Ionic, covalent, and polar covalent bond

8. Covalent Bonding
Equal Sharing of electrons
Each atom fills it’s
outermost energy level
Smallest particle of a
compound is a molecule

9. Ionic Bonding
An ionic bond forms when
one atom gains electrons
and the other loses
electrons
Ions are held together by
their opposite charges
Involves atoms of very
different sizes

10. Chemical reactions
The making or breaking of bonds is called a chemical
reaction
Reactants (chemicals that enter a reaction) & products
(compounds that are produced)
A chemical reaction is indicated by a chemical equation.
Na (+) + Cl (-) ---> NaCl
O2 + 2H2  2H2O

11. Polar Covalent
The unequal sharing between two atoms (usually one
much larger than the other)
Creates slight charge on either side of the molecule.

12. Hydrogen bond
Between hydrogen and another atom such as nitrogen or
oxygen
Weak attractive force that forms temporary, easily broken
bonds

13. Water
importance for living things
Water has an unusual chemical structure
We are over 70% water

14. Properties of water
1. less dense as a solid
Found in all three states (solid, liquid and gass) on the
earth

15. 2. Water is a good solvent. Many compounds dissolve in
water.
3. Water is slow to heat and slow to cool.
4. water is cohesive – water molecules will attract other
molecules
5. water is adhesive- water adheres to other molecules

16. Why?
The bonds are covalent, but the sharing is unequal
The water molecule carries a slight charge
It is polar

17. Hydrogen Bonds
The slight charge attracts other water molecules
This forms weak temporary hydrogen bonds

18. As water changes state it adds or breaks apart hydrogen
bonds. This slows changes in temperature

19. solvent
Some hydogen bonds will pull strongly enough to break off
a hydrogen ion
H2O H(+) + OH (-)
This will ionize a small portion of the water creating equal
numbers of hydrogen and hydroxide ions
solution (solute and solvent)
NaCl  Na+ Cl -

20. In a liter of water only
0.0000001 m/l of water has
ionized. (That’s 1x10 ^-7)
(PH=7)
PH stands for the percent
of hydrogen ions in solution
in relation to hydroxide ions
More hydrogen ions are
added the ph will go down
(example hcl)
If more hydroxide ions (OH)
are added then the PH wil
go up (example. NaOH)