Activity Fold your periodic table so that the f and d blocks are looped Determine the number of valence electrons for each remaining group column Find the pattern Valence Electrons Valence electrons ID: 498504
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Slide1
Valence ElectronsSlide2
Activity
Fold your periodic table so that the f and d blocks are looped.
Determine the number of valence electrons for each remaining group (column).
Find the pattern.Slide3
Valence Electrons
Valence electrons
– Electrons in an atom’s highest-numbered energy level.
e
-
config. for Si:
1s
2
2s
2
2p
6
3s
2
3p
2
Si has four valence electrons.
3s
2
+ 3p
2
= 4 e
-
e
-
config. for C:
1s
2
2s
2
2p
2
C also has four valence electrons.Slide4
Valence Electrons
How many valence electrons does selenium have (element 34)?
e
-
config:
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
4
Se has 6 valence electrons.Slide5
Valence Electrons Shortcut
You can tell how many valence electrons any atom should have by its position in the periodic table.
1
2
3
4
5
6
7
8
2
variableSlide6
Why are the valence electrons responsible for bonding?Slide7
How many valence electrons are in each of the following elements:
Na (sodium)
Mg (Magnesium)
Xe
(Xenon)
Br (Bromine)
C (Carbon)
F (Fluorine)
O
(Oxygen)
K (Potassium)Slide8
Draw a picture to explain why the valence electrons are responsible for bonding between different elements.
Try to use the s & p orbital shapes.Slide9
Octet RuleSlide10Slide11
How many valence electrons do each of the following elements
want to lose or gain
?
Na (sodium)
Mg (Magnesium)
Xe
(Xenon)
Br (Bromine)
C (Carbon)
F (Fluorine)
O (Oxygen)
K (Potassium)Slide12
Now,
estimate the reactivity
of each of the following elements based on the valence electrons.
Na (sodium)
Mg (Magnesium)
Xe
(Xenon)
Br (Bromine)
C (Carbon)
F (Fluorine)
O (Oxygen)K (Potassium)Slide13
Lewis Dot DiagramsSlide14
Lewis
Dot Diagrams
Electron Dot Diagram
– shows the valence electrons of an atom as dots.
Distribute dots around atomic symbol to represent valence electrons.
Should
never
have more than 8 dots.Slide15
Lewis Dot Diagrams
Here are the Lewis diagrams for 8 elements, which have 1 – 8 valence electrons.
Li
Be
B
C
N
O
F
NeSlide16
Draw the Lewis Dot structure
for each of the following elements:
Na (sodium)
Mg (Magnesium)
Xe
(Xenon)
Br (Bromine)
C (Carbon)
F (Fluorine)
O (Oxygen)
K (Potassium)Slide17
Periodic TrendsSlide18
Trends
Atomic radius
Electronegativity
Ionization Energy
How are all these important for bonding to form molecules?Slide19
Atomic Radius
Effect of # of protons.
Effect of # of electrons.Slide20Slide21
High
Electronegativity = Strongly seeks to
take
an electron
Low
Electronegativity = Readily
gives
an electronSlide22
High Electronegativity = Strongly seeks to
take
an electron
Low Electronegativity = Readily
gives
an electronSlide23
High Electronegativity = Strongly seeks to
take
an electron
Low Electronegativity = Readily
gives
an electronSlide24
Energy required for another atom to remove an electron.Slide25
?????Slide26Slide27
Trends
Atomic radius
How is it measured
Electronegativity
Ionization Energy
Melting Point
Boiling Point
Conductivity
How are all these important for bonding to form molecules?Slide28
Predict which elements will react with other elements.