Chemistry Standard 11c & 11e

Chem standard 11c: Students know some naturally occurring isotopes of elements are radioactive, as are isotopes formed in nuclear reactions

Naturally occurring Isotopes & artificial Isotopes
a.) An isotope is an atom that has an identical pair of atomic numbers but different mass numbers
b.) Examples of naturally occurring isotopes are on this chart!
c.)Isotopes have unstable nuclei, therefore are radioactive
1.) Isotopes are Radioactive; they spontaneously decompose, creating new nuclei and producing one or more particles
d.) Isotopes are formed in artificial nuclear reactions by bombarding Alpha particles (for example)into a stable element, and causing collisions to occur, which form isotopes that are radioactive








Chem Standard 11e: Students know alpha, beta, and gamma radiation produce different amounts and kinds of damage in matter and have different penetrations

Alpha, Beta, and Gamma Radiation

a.) Alpha particles are fast moving helium atoms. They have high energy, but due to their large mass, they are stopped by just a few inches of air, or a piece of paper.

b.) Beta Particles are fast moving electrons. Since electrons are lighter than helium atoms, they are able to penetrate further, through several feet of air, or several millimeters of plastic or less of very light metals.

c.)Gamma Rays are photons, just like light, except of much higher energy. Depending on their energy, they can be stopped by
1.)a thin piece of aluminum foil
2.) or they can penetrate several inches of lead.