Wed, 09 May 2012 18:30:36 -0800WeeblyTue, 17 Apr 2012 15:36:04 -0800http://arc-links.weebly.com/2/post/2012/04/post-title-click-and-type-to-edit2.htmlOne of my favorite quotes that applies not only to teaching, but also tutoring is by Albert Einstein - "If you can't explain it simply, you don't understand well enough."

]]>Tue, 17 Apr 2012 15:32:31 -0800http://arc-links.weebly.com/2/post/2012/04/post-title-click-and-type-to-edit.htmlRuby Wossum (11/19/1930 - 2/6/2012) was my former boss and mentor. Before her involvement  in tutoring she was a college professor and before that an elementary school teacher.  It was her inspiration and commitment to education that led me to a career in tutoring.  Ms. Wossum was a pioneer and visionary in tutoring.  When she became director of what was later named the Academic Resource Center, she had the foresight during the period 1990-1991 to set up a multipurpose tutoring center at the former State Technical Institute at Memphis (now part of Southwest Tennessee Community College).  Previously all tutoring at the college had been done in a single room for one content area, math.  Ms. Wossum as director of the Academic Resource Center helped create a tutoring center that provided tutoring in all the major content areas taught at the college.  In addition, a computer lab and a collection of instructional video tapes, and other academic resources were housed in the same building. Ms. Wossum set up a peer tutoring program in 1993 that provided an academic scholarship for students agreeing to become tutors. This program, named by Ms. Wossum as DUCKS (Dynamic Use of Collaborative Knowledge and Skills) became the first in the state of Tennessee to earn the Master Level of Certification with the College Reading and Learning Association (CRLA).

It has been said that "A good teacher is like a candle - it consumes itself to light the way for  others." The light that you lit is still glowing in the many tutors who had the privilege of working under you and your many students.  RIP Ms. Wossum.
]]>Wed, 27 Apr 2011 13:42:31 -0800http://arc-links.weebly.com/2/post/2011/04/general-chemistry-electron-domain-geometry-versus-molecular-geometry.html      A molecule can have a different shape when  referring to its electron-domain geometry than when referring to its molecular geometry.  For example, sulfur dioxide, SO2,  electron-domain geometry is trigonal planar. This is because it has 3 electron domains - the 6 valence electrons for sulfur form 2 single bonds with 2 oxygen atoms and sulfur has one non-bonding lone pair.  Also related to electron-domain geometry is the fact that the sulfur has sp2 hybridization, since its geometry is trigonal planar.
    When referring to the molecular geometry for sulfur dioxide, the molecular geometry is bent.  Note that the bent shape is related to the diffence in electronegativity between sulfur and oxygen (3.5 - 2.5). Since the difference in polarity is greater than zero, SO2 is a polar molecule.  The polarity influences  the bond angle for the bent geometry. The lone pairs are not considered when determining molecular geometry, only the bonds with the atoms are considered.
If the central atom of a molecule has no lone pairs, the molecular geometry and the electron-domain geometry are the same.  For example, carbon tetrachloride, CCl4, has no lone pairs on the central carbon atom.  Its molecular geometry and its electron-domain geometry is tetrahedral. ]]>