Covalent Bonds
Dec 26, 2015
Covalent Bonds
Covalent Bonds
Form when two or more non-metal atoms SHARE electrons.
There is no transfer of electrons.
Covalent Bonds
What holds a covalent bond together?
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Covalent Bonds
These are the three types of chemical bonds that you must know:
Covalent Bonds
Using electronegativity to determine what kind of bond will form
Electronegativity:
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Covalent Bonds
Non-Polar Covalent Bond Electronegativity values for the two atoms are
equal Atoms attract electrons with the same force Electrons are shared equally.
Covalent Bonds
Polar Covalent Bonds Electronegativity values differ significantly Electrons are shared unequally Electrons are found by the atom with the highest
electronegativity.
Covalent Bonds
Ionic Bond Review Electronegativity values are extremely different Electron spends so much time at the atom with
high electronegativity, it is thought as being “transferred” to that atom
Covalent Bonds
Electronegativity Difference and Bond Character
Electronegativity Difference
Type of Bond
0.0 – 0.5 Non-polar covalent
0.6 – 1.9 Polar Covalent
2.0 – 3.3 Ionic
Covalent Bonds
DipolesOccur in polar covalent bonds Electrons spend more time around the atom with higher electronegative chargeGives the molecule a partial positive and
negative charge called a dipole
Covalent Bonds
Dipoles Symbol: Lower case Greek Delta (δ) Means “partial” δ+ stands for the positive end
of the molecule δ- stands for the negative
end of the moleculeTHIS IS DOES NOT MEAN THEBOND IS IONIC! This just show where the electron is mostly
likely to be located!
Important!
Properties of Covalent Substances
Soft Poor conductors of heat Poor conductors of electricity
There are no charged particles – no ions Low melting and boiling points due to weak
attraction between molecules Low solubility in water Can be liquid, solid or gas