6-2-2. Explain the relationships between potential energy, distance between approaching atoms, bond
length, and bond energy.
Bonds are most stable when the potential energy of the bonded atoms is minimized.
Bond length: The distance between two bonded atoms at their
minimum potential energy, or the average distance between
two bonded atoms.
Bond energy is the energy required to break a chemical bond and
form neutral isolated atoms
Electron-dot notation is a notation with only the valence electrons
of an atom of a particular element are shown, indicated by
dots placed around the element’s symbol.
A molecule is a neutral group of atoms held together by covalent
bonds.
A molecular formula shows the types and numbers of atoms joined
in a single molecule of a molecular compound.
Octet Rule: Chemical compounds tend to form so that each
atom, by gaining, losing, or sharing electrons, has an octet (8)
of electrons in its highest occupied energy level.
6-2-4 The six basic steps used in drawing Lewis structures.
1. Determine the type and number of atoms in the molecule.
2. Write the electron-dot notation for each type of atom in the molecule.
3. Determine the total number of valence electrons in the atoms to be combined.
4. Arrange the atoms to form a skeleton structure for the molecule. If carbon is present, it is the central
atom. If not, the least-electronegative atom is central (normally the atom that is closest to carbon on
the Periodic Table).
5. Add unshared pairs of electrons so that each hydrogen atom shares a pair of electrons and each other
nonmetal is surrounded by eight electrons.
6. Count the electrons in the structure to check that the number of valence electrons used equals the
number available.
Homework: Section Review: p. 175. #’s 1 - 2.
Chapter Review: p. 195 #’s 6 -10.
