Transcript Principles of Matter and Energy

Principles of Matter
and Energy
Outline
I What is Matter
A. Elements
B. Compounds
II Atoms
A. Components
B. Ions
C. Isotopes
D. Energy
III Types of Bonds
A. Ionic
B. Covalent
IV Chemical Reactions
What is Matter?

Matter:

Unit of matter is the atom
Matter consists of elements which are
combined to form molecules and
compounds

Elements

Exs: H hydrogen, O oxygen, He helium, Ca
calcium, Au gold
Compounds

Molecule:
Components of Atoms

Atom:
Components of Atoms

Made up of three types of particles:
–
Protons:
–
Neutrons:
–
Electrons:
Ions

Usually #protons = #electrons
–

Atom has no net charge = neutral
Ion:
–
Cation:
–
Anion:
Isotopes

Atoms of the same element that differ in atomic
mass

Examples:
Isotopes

Radioactive isotopes: nucleus decays
spontaneously releasing high-energy
electromagnetic radiation, subatomic particles,
or both
Isotopes

Half-life:

Example: Tritium (3H) decays into 3He with a
half-life of 12.5 years

Some isotopes have very short half-lives (e.g.
iodine) while others are extremely long (e.g.
plutonium, a waste product of nuclear power
reactions, has a half-life of 24,000 years.
Isotopes
–
By determining ratios of the different isotopes of
carbon and other elements in samples of biological
origin and in rocks, scientists are able to determine
with certainty when these materials formed.

–
Half-life cannot be changed by temperature, pressure,
chemical reactions, or any other environmental factor.
Another use of isotopes is in medicine-tracking
physiological processes. E.g. isotope of iodine used
to check for thyroid problems
Energy Within the Atom
Chemical Bonding

Chemical Bond:
Ionic Bonds

Example:
Covalent Bonds

Electronegativity:
Non-polar Covalent Bonds

Examples
Polar Covalent Bonds

Examples
Hydrogen Bonds

Example
Molecular Shape and Function

Examples
Chemical Reactions