Dakota Frizzell and Alex Hite

 Atoms are incredibly small clusters of even smaller subatomic particles  Atom is Greek for “ incapable of being divided”  Atoms can be divided under very special circumstances, but lose their unique properties when done so

(Electric charge is a measure of a particles ability to attract or repel other charged particles)  Atoms of elements are composed of different numbers and proportions of 3 basic subatomic particles.  Protons: positive charge  Neutrons: neutral, or no charge  Electrons: negative charge

 Planetary models portray atoms as a miniature solar system, with protons and neutrons in the middle and electrons orbiting around in generally circular paths.  Orbital models depict the general location of electrons outside the nucleus in a haze of negative charge

 All protons, electrons, and neutrons are alike. What makes the elements different is the amount of each of these.  For example: Hydrogen (H)- 1 proton, 1 electron, and 0 neutrons, while Helium (He)- 2 protons, 2 electrons, and 2 neutrons.

 Atomic number is equal to how many protons there are.  Atomic mass is the sum of protons and neutrons contained in the nucleus.

 Atomic weight approximately equal to mass number of most abundant isotope  Isotopes have the same number of electrons, but different numbers of neutrons

 Heavier isotopes of certain atoms are unstable, and tend to decompose to become more stable. These are called radioisotopes. This process is called radioactivity.  This can be compared to a tiny explosion. It involves ejection of alpha or beta particles or gamma rays (electromagnetic energy), which is damaging to living cells

 Alpha particles leave the least effect, while gamma rays do the most damage.  PET scans use radioisotopes to tag onto cells in the body. Radioisotope of iodine can be used to scan thyroid gland. Radium, cobalt, and others used to destroy some cancers.

 Marieb, Elaine, “Atomic Structure” and “Identifying Elements”, Essentials of Human Anatomy and Physiology, Serina Beauparlant, 8 th edition, San Francisco, Pearson Benjamin Cummings, 2006, “ pgs ”