2.1: How Matter is Organized

Chemistry

The science concerned with the structures, properties, and changes of matter

Solid

A phase that has definite shape and volume

Liquid

A phase that has definite shape and indefinite volume

Gas

A phase that has indefinite shape and volume

Matter

Anything that occupies space and has mass

Atoms

A basic, fundamental unit of matter

Elements

The different types of atoms; there are 118 different types

Major Elements

Elements that make up 96% of the body: Oxygen, Carbon, Nitrogen, Hydrogen

Lesser Elements

Elements that contribute to 3.6% of the body: Calcium, Magnesium, Phosphorus, Potassium, Sulfur, Calcium, Iron

Trace Elements

The fourteen elements that make up 0.4% of the body

Proton

Positively charged particles that gives off a charge of +1 and has a mass of 1 amu

Neutron

No charged particles that gives off a charge of 0 and has a mass of 1 amu

Electron

Negatively charged particles that gives off a charge of -1 and has a mass of 0.0005 amu

Electron Shell

The maximum number of electrons each shell can hold

• First shell: 2 electrons

• Second shell: 8 electrons

• Third shell: 18 electrons

Atomic Number

The number of protons (elemental identifier)

Mass Number

The sum of the number of protons and neutrons

Isotopes

The different variants of an element that has the same number of protons but different number of neutrons

Radioactive Isotopes

Rare and unstable isotopes that would decay over time until it becomes stable, and would release energy/radiation in due process

Half-Life

The time required for half of the radioactive isotopes to become stable

Uses of Radioisotopes

• Carbon-14: Used and biological research, agriculture, pollution control

• Cobalt 60, Cesium 137, Copper 67: cancer treatment

• Phosphorus 32, Sulfur 35, Cobalt 60: Used in genetic and molecular biology

• Tritium: Used for life science and drug metabolism studies to ensure the safety of potential new drugs

• FDG: Studying internal organs, such as PET scanning

• Cobalt 60: Sterilization of syringes and medical equipment

• Chromium-51: Used in the studies of red blood cells arrival

Chernobyl

A nuclear meltdown accident in Japan that killed more than 31 people, contaminated surrounding environment with with radioactive waste, expose many to cancer

Atomic Mass

The average mass of all naturally occurring isotopes

• The most abundant isotope best reflect the atomic mads