Covalent Bonds Review Reactivity – Electron configuration – Stability Chemical bond Lewis dot...
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Transcript of Covalent Bonds Review Reactivity – Electron configuration – Stability Chemical bond Lewis dot...
Covalent Bonds
Review
• Reactivity– Electron configuration – Stability
• Chemical bond• Lewis dot symbol
Covalent bond
• Bond in which two valence electrons are shared by two atoms– Occurs with elements close to each other on the
periodic table– Ex: H2O, NH3 (ammonia), CH4 (methane)
– Between a nonmetal and a nonmetal
3 Types of Covalent Bonds
• Single Covalent Bond• Double Covalent Bond• Triple Covalent Bond
3 Pencil Demo for Single, Double and Triple Covent bonds
• Make as many observations as you cani.e. facial expressions, body position, muscles
used, noises made, force or energy exerted, etc.
Single Covalent Bonds
• Each atom shares one pair of electrons• Each atom shares 2 electrons• Longest bond• Weakest bond of the three
H—H
Lewis Structur
e
Double Covalent Bonds
• In a double bond, each atom shares two pairs of electrons
• Each atom shares 4 electrons• Medium length bond• Medium strength bond
Lewis Structur
e
O2
Triple Covalent Bond
• In a triple covalent bond, each atom shares three pairs of electrons
• Each atom shares 6 electrons• The shortest bond• The strongest bond• Carbon, nitrogen, oxygen, and sulfur can form
double and triple covalent bonds
N2
Lewis Structur
e
Strength of Covalent Bond
• Several factors control bond strength—Number of shared electrons-the more
electrons shared, greater the bond—Size of the atom—Bond length – the greater the bond length,
the weaker the bond
SubstanceMolecule• Two or more atoms
chemically bonded together
Compound• Two or more elements
chemically bonded together
MoleculesDiatomic
CO
HCl
Memeorize Diatomic Elements
– elements that exist as two
H2, O2, N2, Cl2, Br2, I2, F2
– HONClBrIF– Magnificent 7-don’t forget H
MoleculesPolyatomic
O3
H2ONH3
CO2
CompoundMolecular Compound
HCl CO
H2ONH3
CO2
Binary Molecular Compound
Covalent Molecule Properties
• Covalent molecular solids tend to be soft solids, liquids, or gases at room temperature
• Low melting and boiling points• Poor conductors of heat and electricity• Non-electrolytes – do not conduct electricity
in water