Atomic Structure and Identifying Elements

Dakota Frizzell and Alex Hite

Atomic Structure

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 chargeNeutrons: neutral, or no chargeElectrons: negative charge

Planetary and Orbital Models

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

Identifying Elements

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.

Identifying Elements

Atomic number is equal to how many protons there are.

Atomic mass is the sum of protons and neutrons contained in the nucleus.

Identifying Elements

Atomic weight approximately equal to mass number of most abundant isotope

Isotopes have the same number of electrons, but different numbers of neutrons

Identifying Elements

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

Identifying Elements

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.

Citation

Marieb, Elaine, “Atomic Structure” and “Identifying Elements”, Essentials of Human Anatomy and Physiology, Serina Beauparlant, 8th edition, San Francisco, Pearson Benjamin Cummings, 2006, “ pgs. 29-32”