it14spr101.40DC2T1 2 3.txt

• A. Anything that has weight and takes up space
• B. Is composed of elements

• The study of composition of substances How the substances change

The study of composition of substances and how the substances change

Fundamental substances which comprise all matter, it is composed of particles called atoms, examples of elements are iron, copper, silver, gold, aluminum, carbon, hydrogen, oxygen.

• 1. Bulk elements
• -Are elements needed by the body in small amounts
• -6 examples of bulk elements are carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorous.

• 2. Trace Elements
• -are elements needed by the body in small amounts
• -trace elements are used by the body for parts of enzymes.

• 3. Ultratrace Elements
• -are elements needed by the body in very small amounts
• -are toxic in large amounts

Chemical combinations of elements.

Nucleus and electron shells and are the smallest particle of an element that has properties of that element.

The central portion of an atom, it contains protons and usually neutrons and is has no weight

Located circling around the nucleus and carry a negative charge

Located in the central portion of an atom and carry a positive charge.

Located in the central portions of an atom and are electrically neutral

The number of protons in the atoms of a particular element. Ex: Carbon has an atomic number of 6 because it has 6 protons.

• The number of proton plus the number of neutrons in each of an element’s atoms. Primarily due to the weight of protons and neutrons. Atoms of the same element can vary in atomic weights because their number of neutrons may vary. Example: one carbon atom has six protons and six neutrons—the atomic weight of carbon=12

• Atoms that have the same atomic numbers but different atomic weights (different # of neutrons). Radioactive isotopes release atomic radiation. Examples of radioactive isotopes are isotopes of oxygen, iodine, iron, phosphorus, and colbalt.

When atoms combine with themselves or other atoms.