Organic Chemistry Key Concepts: Topic 0
-The number in the upper right of a given atom on the periodic table is the number of valence electrons
(the number of unpaired electrons in the valence shell). The lower right denotes the atom’s
-Electronegativity reflects an atom’s ability to “attract a shared pair of electrons to itself.”
Electronegativity values increase up and to the right of the periodic table.
-Polar bonds result from the unequal sharing of electrons between unlike atoms with electronegativity
differences < 1.9, but > 0.5. As a note, rank hydrogen as having relatively the same electronegativity
value as carbon. Sometimes the dipoles of polar bonds cancel each other out, so the molecule itself is
non-polar (has no net-dipole moment). The 3D structure of a molecule needs to be known before its
overall polarity can be recognized.
-Formal charge describes if the n