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Learn about single, double, triple, and coordinate covalent bonds and the rules for writing Lewis dot structures for molecules and polyatomic ions.
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-Types of Covalent Bonds-Rules for Writing Lewis Dot Structures of Molecular Compounds Chemistry Mrs. Coyle
Single Covalent Bond Fluorine
Single Covalent Bonds in a Structural Formula • The electron pair is shown as a line F-F • Unshared electrons can be shown as dots.
Double Bond • Two electron pairs are shared O :: O O = O
Carbon Dioxide, CO2 O=C=O
Triple Covalent Bond Three pairs of electrons are shared. :N:::N: :N N:
Coordinate Covalent Bond • When one atom contributes a pair of bonding electrons. ·C· + :O: :C::O The oxygen atom made the contribution.
Polyatomic Ions • A tightly bound group of atoms that behave as a unit and have a charge.
Rules for Writing the Lewis Dot Structure for a Molecule • Sum all the valence electrons of each element in the molecule. • Draw the skeletal structure of the molecule and put a single bond between each element. • If there are more than two elements, you usually put the least electronegative one in the center.
Rules (Cont’d) • Draw the electrons in the surrounding atoms, so that each atom will have a complete octet (duet for H). • Add the remaining electrons to the central atom. • Check that each atom has no more than an octet (duet for H). • Check that the total electrons drawn equal the total available valence electrons found in step 1.
Single Covalent Bonds • Write the structural formulas for: Cl2 NH3 CH4 H2O
Polyatomic Ions • Draw the electron dot structures for: CO32- NO3- SO32- SO42-