Principles of Matter Principles of Matter and Energyand Energy

Outline

I What is Matter III Types of Bonds

A. Elements A. Ionic

B. Compounds B. Covalent

II Atoms IV Chemical Reactions

A. Components

B. Ions

C. Isotopes

D. Energy

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