1. Understanding the Periodic Table

2. ARRANGEMENT OF PERIODIC TABLE
Mendeleev arranged elements by increasing atomic number

3. Subatomic particles Protons- positive charge - nucleus
Neutrons- neutral (no) charge - nucleus
Electrons- negative charge – outside the nucleus

4. Atomic Number Number assigned to element that appears above the symbol
Atomic number = protons = electrons 5 B
Boron
10.81

5. Atomic mass (rounded off) – atomic number = neutrons
Also referred to as atomic weight or (amu) atomic mass unit
Atomic mass (rounded off) – atomic number = neutrons 5 B
Boron
10.81

6. NEVER TWO CAPITAL LETTERS FOR ONE ELEMENT
Chemical Symbol
A capital letter or a capital letter and one lower case letter
NEVER TWO CAPITAL LETTERS FOR ONE ELEMENT

7. Let’s practice what we know so far
Element
Symbol
Atomic #
Protons
Neutrons
Electrons
Nitrogen
Carbon
Neon

8. Groups or Families Vertical columns on the periodic table
There are 18 of them
Each family has a family name

9. Periods
Horizontal rows on the periodic table
There are 7 of these

10. Other things we can tell about the element…
Remember the 7 periods?
The period tells us how many rings (shells, orbits, clouds or energy levels) the element has
Argon is in period 3, so it will have 3 rings

11. Remember the group number?
There are 18 groups (families) and if you look at the group number…the ones column of the group number…that will tell you the number of valence electrons the atom will have! Atoms in group 14 will have 4 valence electrons. Family 2 has 2.

12. Valence Electrons
These are the electrons found on the outermost shell

13. Now let’s look at the electrons…
Element
Symbol
Atomic #
Protons
Neutrons
Electrons
Oxygen O 8
Element
Period
Family/group
Oxygen 2 16

14. What is this? You will need this.
Shell K L M N O P Q
# of electrons 2 8
8 or 18
8 or 32
The sure-proof guide to Electron Distribution
1.The number of electrons is equal to the number of protons (atomic number)
2. The number of orbits (shells) is equal to the period number of the elements
3.The number of electrons in an element’s outer orbit (valence) (this is to be filled first) is equal to its group number (ones column only)
4. Then fill from “K” shell to the outside. Your inner shell must be filled (complete) before you move on to the next shell

15. More about electrons… Why do atoms combine? To Be “Happy” AKA “Stable”
The “law” of Electrons
 All atoms want to have eight electrons in their outer energy level, unless that energy level is the “K” or “Q” energy level, then they want two

16. Bohr model
Element
Period
Family/group
Oxygen 2 16
# of shells
# of valence electrons
We know that Oxygen has 8 electrons. It will have 2 shells since it is in period 2. It will have 6 outermost electrons. We look at the group/family number (the ones column only)

17. Let’s do one…

18. One more…

19. Lewis Dot Diagram
Use the symbol of the element and the number of valence electrons and place a dot to represent the number of valence electrons with a dot.
Begin to the right of the symbol and go counter clockwise.
There will never be more than 8 dots since there will never be more than 8 valence electrons. Al 2 3 1

20. Now you try… Ge

21. What did we learn? The arrangement of the periodic table
What subatomic particles are
How to read the periodic table
What valence electrons are
How to create Bohr Models
Family Names of the periodic table
How to create a Lewis Dot Diagram