What is a Valence Electron Valence electrons are the electrons in the outer shell that bond with other atoms What is a Valence Electron Valence electrons are the electrons in the outer shell ID: 623091
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Slide1
Valence ElectronsSlide2Slide3
What is a Valence Electron?
Valence electrons
are the electrons in the outer shell
that bond with other atomsSlide4
What is a Valence Electron?
Valence electrons
are the electrons in the outer shell
that bond with other atoms
= valence electronSlide5
What is a Valence Electron?
Valence electrons
are the electrons in the outer shell
that bond with other atoms
= valence electronSlide6
What is a Valence Electron?
Valence electrons
are the electrons in the outer shell
that bond with other atoms
Core electrons
are
under valence electrons
= valence electronSlide7
Outer Shells of Electrons
The number of valence electrons determines an
e
lement’s chemical properties
For example, the noble gases on the right side of the
periodic table are inert
Inert
= do not react with other atomsSlide8
Noble Gases
Noble gases are inert because they have 8 outer shell (=valence) electrons
Having 8 outer shell electrons means
the outer shell
is full, and therefore can’t reactSlide9
Periodic Table Groups
Columns on the periodic table are called
GROUPS
Elements in the same group have similar chemical properties.
This is because each group has the same number of valence electronsSlide10
Valence Electrons in Groups
Elements in the periodic table are arranged in
groups.
Each group has the same number of valence electrons….
Group 1A
Group 2A
Group 4A
Group 6A
Group 7A
Group 8A
Group 3A
Group 5A
Group 1A has 1 valence electron, group 2A has 2 valence electrons, group 3A has 3 valence electrons……….Slide11
Importance of Valence Electrons
The entire periodic table is arranged according to the number of valence electrons each element has!!
The reason they arrange the periodic table this way is because elements in each group react similarly (=same)Slide12
Octet Rule
The
octet rule
states that atoms like to have 8 valence electrons.
Atoms that have 8 outer shell electrons are stable and non reactive.
The noble gases (group 8A) are stable
b
ecause they all have 8 valence electronsSlide13
Lewis Structures
Lewis structures show ONLY valence electrons.
Examples
:
Sodium (Na) is in group 1A, so we know it has 1 valence electron. Group 1A is known as the
alkali metals
Beryllium (Be) is in group 2A, so we know it has 2 valence electrons. Group 2A is known as the
alkaline earth metalsSlide14
Lewis Structures
Lewis structures for oxygen
Oxygen is in group 6A, so it has 6 valence electrons.Slide15
How to Draw Lewis Structures
Look at the element you want to draw the structure for and see what group it is in.
D
raw dots around the symbol according to how many valence electrons it has.
Example: Draw a Lewis Structure for calcium
We see calcium (
Ca
) is in group 2A, so it has 2 valence electrons
CaSlide16
Questions
What is a valence electron? Draw an atom and show the valence electrons.
How many valence electrons do the following elements have:
Si, C, O,
Ar
, K
What does inert mean?How many valence electrons do atoms like to have?
What do “groups” on the periodic table have in common?Draw the Lewis structure for the following elements: Ne, P, Mg, Na, Pb
, Sb