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Slide 1
Slide 2
Electrons are the negatively charged part of the atom Electrons
are found in orbitals around the nucleus We write the electron
configuration of the element to see the different orbitals the
electrons are located in
Slide 3
Write the electron configuration for Lithium Write the electron
configuration for Fluorine
Slide 4
The electrons in the last energy level of the element are the
VALENCE electrons The last energy level is the part of the
configuration that has the largest number in front of it Lithium =
1s 2 2s 1 Fluorine = 1s 2 2s 2 2p 5
Slide 5
An element can have anywhere from 1-8 valence electrons The
number of valence electrons determines how REACTIVE the element is
8 = totally unreactive 1 and 7 = extremely reactive 2 and 6 =
pretty reactive 3-5 = only kinda reactive
Slide 6
Pull out your periodic table! You can find the valence electron
of the element by seeing what group it is in. Where are the groups
on the periodic table?
Slide 7
You should already have groups 1-18 listed on your periodic
table Group 1 = 1 Valence Electron Group 2 = 2 Valence Electrons
Group 13 = 3 Valence Electrons Group 14 = 4 Valence Electrons Group
15 = 5 Valence Electrons Group 16 = 6 Valence Electrons Group 17 =
7 Valence Electrons Group 18 = 8 Valence Electrons
Slide 8
The transition metals in groups 3-12 have their own set of
rules Dont worry about them for now
Slide 9
Write down the following elements on a sheet of paper next to
them find out how many valence electrons they have? 1. Neon2.
Sodium 3. Aluminum 4. Calcium 5. Sulfur 6. Iodine 7. Carbon 8. Lead
9. Phosphorus 10. Krypton
Slide 10
Slide 11
How many valence electrons does Arsenic have? How many valence
electrons does Potassium have?
Slide 12
To find the number of valence electrons for the elements in
groups 1,2 and 13-18 you look at your periodic table Transition
metals (groups 3-12) have their own rules
Slide 13
To find the number of valence electrons for a transition metal
you have to write the shorthand electron configuration for that
metal For example Irons shorthand electron configuration is [Ar] 4s
2 3d 6
Slide 14
Just like the regular valence electrons, we look at the highest
energy level Irons shorthand electron configuration is [Ar] 4s 2 3d
6 4s 2 = highest energy level Iron has 2 valence electrons
Slide 15
All transition metals will have a shorthand configuration that
gives you 2 valence electrons However, Transition Metals can act
like they have anywhere from 1-4 electrons
Slide 16
Valence Electrons side of worksheet For each question you
should 1. Write the shorthand electron configuration 2. Write how
many valence electrons each element has
Slide 17
Slide 18
By now we know that an element can have anywhere from 1-8
valence electrons We can find the number of valence electrons the
element has by looking at the periodic table or by its electron
configuration
Slide 19
For Groups 1,2, 13-18 the number of valence electrons depends
on group it is in Exception! Helium is a noble gas and is full, but
because of its electron configuration it has 2 valence electrons,
not 8 Transition metals in groups 3-12 all have 2 valence
electrons, even though they dont always act that way
Slide 20
We can draw Lewis Structures to represent the valence electrons
of an element To draw a Lewis Structure 1. Put the element symbol
in the middle 2. Determine how many valence electrons it has 3.
Draw a dot for each electron around the symbol
Slide 21
As you are putting the dots around the symbol you start by
putting one dot on each side of the symbol No side should ever have
more than 2 dots Example: Electron dot diagram for Carbon : C:
C
Slide 22
Draw the electron dot diagram 1. Put the element symbol in the
middle 2. Determine how many valence electrons it has 3. Draw a dot
for each electron around the symbol NaClMgAr
Slide 23
Lewis Dot Diagrams side of worksheet Remember, Helium is an
exception to the noble gases, it only has 2 valence electrons!