A visual representation of covalent compounds
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1. Octet Rule
◦ Covalent compounds share electrons so that each atom
has an octet of electrons (8) in its highest energy level.
 Exceptions:
 Hydrogen has a full valence shell at 2 electrons
 Boron has a full valence shell at 6 electrons instead of 8
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2. Single Bonds
◦ 1 electron pair is shared (a total of 2 electrons)

3. Double Bonds
◦ 2 electron pairs are shared (a total of 4 electrons)
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4. Triple Bonds
◦ 3 electron pairs are shared (a total of 6 electrons)
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Electron-dot notation can also be used to represent the structure of molecules,
called Lewis Structures.

The pair of dots between the two symbols represents the shared electron pair of
the hydrogen-hydrogen covalent bond.
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In addition, each fluorine atom is surrounded by three pairs of electrons that are
not shared in bonds.
An unshared pair, also called a lone pair, is a pair of electrons that is not involved
in bonding and that belongs exclusively to one atom.
Step 1
 Get a covalent formula and draw the
electron-dot notation for each atom in the
formula.
Step 2
 From the electron-dot notation, determine
how many bonds each atom needs to get an
octet.
Step 3
 Determine the central atom (Skip this step if
there are only 2 atoms):
◦ Carbon is always the central atom
◦ If there is more than 1 carbon they make a chain in the
center.
 -C-C-C-
◦ Hydrogen & group 17 elements are never in the center.
◦ The least electronegative is in the center.
Step 4
 Spread the remaining elements around the
central atom & bond each to the center