1. The Periodic Table

2. A Brief History…
Greek thinkers (400 BC) used the words element and atom to describe the differences and smallest parts of matter.
Lavoisier divided the few elements known in the 1700's into four classes, and then John Dalton suggested that the mass of an atom was it's most important property.

3. More History
Mendeleyev used the periodic table show chemical periodicity and to determine properties of missing elements.
Since Mendeleyev had the insight to use the periodic table as a predictive tool, he is generally credited with discovering the periodic table.

4. How are elements arranged?
By number of protons
By atomic weight
By chemical properties

5. A row is called a period
A column is called a group or family

6. Periodic Law
When the elements are arranged in order of increasing atomic number, there is periodic pattern in their physical and chemical properties.
Makes it MUCH easier to remember the chemical and chemical properties of the elements.

7. Elements are also arranged by groups/families
Alkali Metals
Alkaline Earth Metals
Transition Metals
Other Metals
Metalloids
Non-Metals
Chalcogens
Halogens
Noble Gases
Rare Earth Elements

8. Alkali Metals Group 1A – One valence electron Very reactive metals
Do not occur freely in nature
Malleable, ductile, and good conductors of heat and electricity
Softer than most metals
Explode if exposed to water

9. Alkaline Earth Metals Group 2A – 2 valence electrons
Metallic elements found in second group of periodic table
Also very reactive, not found freely in nature

10. Transition Metals Ductile and malleable Conduct electricity and heat
Valence electrons present in more than one shell
Iron, cobalt, and nickel are the only transition metals known to produce a magnetic field

11. Other Metals
Ductile and malleable but not the same as transition elements
Only a few exhibit variable transition states
High density
Opaque

12. Metalloids
Found along the stair-step line that divides metals from non-metals
Have properties of metals and non-metals
Some are semi-conductors meaning they can carry electrical charge

13. Non-Metals Do not conduct electricity or heat well Very brittle Dull
Exist as gas and solids

14. Chalcogens 6 valence electrons, form 2- ions
Name from the Greek “ore formers,” also known as the “oxygen” group.
Increase in metallic character moving down the group.

15. Halogens 7 valence electrons, from 1- ions Form Salts
Exist in all three states of matter
Very reactive

16. Noble Gases Considered unreactive until the 1960s
Have maximum number of electrons possible for their outer shell making them stable

17. Rare Earth Elements Lanthanide and actinide series
Many are synthetic or man made
All actinides are radioactive