 Valence
electrons are the electrons in the
outer orbit of an atom
 These electrons determine the chemical
bonding properties of elements.
 The number of valence electrons an atom
has corresponds to its group number with the
exception of groups 3-12.
 This is why elements within a group usually
have similar properties.
Be (Beryllium)
Atom
Mg (Magnesium) Atom
 The
number of energy levels an atom has
corresponds to the period number (row
number).
 These
are the total number of rings you have
in your Bohr Diagrams
4th Shell
K (Potassium) Atom
Kr (Krypton)
Atom
Fe (Iron) Atom
A
way of representing atoms by showing the
number of valence electrons as dots
surrounding the element symbol
 Example:

Oxygen gets 6 dots.

Chlorine gets 7 dots.
 There
 So
is an order we fill the dots
it would look like this, depending on how
many valence electrons we have.
Please construct Lewis Structures for the
following atoms:
1
Calcium (20)
2
Antimony (51)
3
Bromine (35)
4
Indium (49)
5
Cesium (55)
6
Lead (82)
7
Tellurium (52)
8
Radon (86)
9
Strontium (38)
10 Helium (2)
1
2
3
4
5
6
Which element has 5 valence electrons and 3
energy levels?
Which element has 4 energy levels and 6
valence electrons?
How many energy levels and valence electrons
does Astatine have?
How many valence electrons and energy levels
does Tin have?
How does the mass of Argon compare to
Mercury? Why?
How does the mass of Potassium compare to
Copper? Why?