Diatomic = “di” + “atomic” “di” = Greek prefix; means “two” QUESTION: Which of these elements naturally occurs as a diatomic gas under ordinary conditions? A. bromine, B. iodine, C. mercury, D. chlorine Diatomic = “di” + “atomic” “di” = Greek prefix; means “two” Diatomic molecule: made up of two atoms There are only seven elements known to naturally exist as diatomic molecules under ordinary conditions. H2, N2, O2, F2, Cl2, Br2, I2 SCRIPT: Which of these naturally occurs as a diatomic gas under ordinary conditions? A. bromine, B. iodine, C. mercury, D. chlorine PAUSE The term diatomic comes form the greek prefix di… and atomic CLICK Di… means two. Therefore, a diatomic molecule is a molecule that is made up of two atoms. CLICK There are only seven elements known to naturally exist as diatomic molecules under ordinary conditions. HIGHLIGHT each element as they are called. Hydrogen… nitrogen.. Oxygen… fluorine… chlorine…bromine… and iodine Note that when we are referring to these elements as they occur in nature, we indicate a subscript of two next to the symbol for the element. HIGHLIGHT subscripts Obviously, … mercury is not the correct answer. CROSS OUT mercury The question is, … which of the remaining three choices… bromine, iodine, and chlorine… is gaseous under ordinary conditions? The answer is chlorine. Bromine is a liquid and iodine is a solid. It might help you to remember these elements by looking at where they are located in the periodic table. CONTINUED ON NEXT SLIDE

Gaseous, diatomic Liquid, diatomic Solid, diatomic Here they are… Hydrogen CLICK nitrogen CLICK Oxygen Chlorine Hydrogen, nitrogen, oxygen, fluorine, and chlorine are all gaseous under ordinary conditions Bromine is a liquid under ordinary conditions. CLICK CLICK And iodine is a solid under ordinary conditions. PAUSE CLICK PAUSE END RECORDING Gaseous, diatomic Liquid, diatomic Solid, diatomic

Video ID: 1-7-3 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08