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What is an ionic bond?
What was the overall goal of the ionic bond?
What molecules are most likely to form ionic
bonds with eachother?
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What do you think an covalent bond is?
Can you think of a picture of a covalent
molecule?
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What holds the atoms together?
What can form a covalent bond with what?
How many covalent bonds can form?
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Covalent bond is the bond formed by the
sharing of electrons between atoms
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H + H ---> H2 making bonds release energy
H2 ---> H + H requires energy to break bonds
Molecular compounds have less energy and are
‘more stable’
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Electrons attract the positively charged nuclei
They screen the positive charges of the nuclei
allowing them to be closer than usual
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H2
F2
H20
NH3
CH4
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A covalent bond is the sharing of electrons
between atoms
Forming a covalent bond releases energy,
breaking a bond takes energy
Molecular compounds are more stable than
their singular components
The shared electron screen the nuclei of the
atoms, allowing the atoms to be closer together
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In covalent bonds, electron sharing usually
occurs so that atoms attain the electron
configuration of noble gases, or in other words,
they share electrons to satisfy the octet rule.
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O2
N2
CO2
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Bond dissociation energy- the amount of
energy required to break a bond
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A bond where one atom contributes both
bonding electrons
Ex. CO
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A resonance structure is a structure that occurs
when it is possible to draw two or more valid
electron dot structures
Ex. 03
The actual bonding is a hybrid or mixture of
the resonance structures
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PCl5
SF6
NO2
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The sharing of electrons isn’t always equal.
Electronegativity is the ability of the atom to
attract electrons when the atom is in the
compound
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Polar bond is a covalent bond where electrons
are shared unequally
Nonpolar is a covalent bond where electrons
are shared equally
In a polar bond, the more electronegative atom
attracts the electron more strongly and gains a
slight negative charge
The less electronegative atom has a slight
positive charge
0.0 – 0.4 nonpolar covalent
0.4 - 2.0 polar covalent
> 2.0 ionic
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Weaker than ionic or covalent
Van der Waals Forces
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Dipole interactions - between polar molecules
Dispersion forces – motion of electrons
Hydrogen bonds – strong attraction between
hydrogen and O, F, N
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Because hydrogen is ‘special’
Lack of shielding
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Haikus are three line Japanese poems where
the first line has five syllables, the second has
seven syllables, and the third has five syllables.
Write a haiku about how the electrons behave
when a covalent compound is formed