1. Vocabulary and Notes 8th grade Science
The Periodic Table
Vocabulary and Notes
8th grade Science
Power points are for you to use it you want. Feel free to edit to fit your classroom.

2. Vocabulary
Physical property – observable characteristics of matter without it changing into something else (density, melting point)
Chemical property – observed when matter interacts with other matter (flammability)
Atomic mass – average mass of 1 atom of an element
Symbol –one or two letters that stand for an element
Group – elements in a column in the Periodic Table
Periods – horizontal row of the Periodic Table

3. History of Periodic Table
1830 – have 55 elements and no idea of atomic numbers
Did feel that elements could be organized in some manner
1860 –Dimitri Mendeleev discovered system
Was a Russian scientist, wrote facts about elements on cards and organized cards
Noticed patterns appearing when organization based on increasing atomic mass
Portrait of Dimitri Mendeleyev by Ilya Repin

4. Organization
Atomic numbers increase from left to right and top to bottom
Elements with same properties were placed in the same group (vertical column) – also known as a family
Family name based on first element in column
When placed in order of atomic mass and properties didn’t match - new group created
Have 18 groups or vertical columns –numbered 1 thru 18
Left spaces if needed, confident that elements would be discovered that fit group and properties

5. Organization cont. Each horizontal row called a period
Have 7 periods – part of periods 6 & 7 have been separated out and appear as rows below main section – keeps table from being too wide
Can predict physical and chemical properties based on where the element is located on table

6. Periodic Table

7. Square in Periodic Table
Square for each element usually includes atomic number, symbol, name, and atomic mass
Sometimes will have other information depending on the table 20
Ca calcium
40.08

8. Let’s Look at Some Groups in the Periodic Table

9. Metals 75% of elements considered metals
Are good conductors of electricity and heat
Are very reactive – most form compounds very easily by giving up valence electron (s)
Easily combine to form alloys
Are malleable and ductile

10. Group 1 The Alkali Metals
Known as alkali metals- most reactive family
Are soft, silver-gray, light weight
Melting points decrease as you go down the group
Melt at low temperatures
Have 1 electron in outer shell which makes them very reactive
When put in H2O some will explode

11. Group 2 The Alkaline Earth Metals
2nd most reactive group
Have 2 electrons in outer shell – are generally found combined with other elements
When mixed in a solution will produce a solution with ph > 7
This is why called alkaline or base metals

12. Transition Metals Include a lot of elements
Group has many electrons and will share them in many ways
Able to put up to 32 electrons in second to last shell- which is the maximum
Able to use last 2 outer most shells for bonding which makes them have a wide variety of properties

13. Group 7 Halogens
Have 7 electrons in outer shell – makes them as reactive as alkali metals
Often bonds with metals and elements in group1
Less reactive as go down the chart

14. Inert Gases Called noble gases
Least reactive of all as have full outer shells
Rarely combine with other elements – called inert
As you move down the family gases become rarer
Used all over world in signs, balloons, headlights, etc.

15. Lanthanides Considered rare-earth metals Found naturally on earth
Only one is radioactive

16. Actinides All radioactive
Some not found in nature – are made only in high tech laboratories and do not last very long

17. Two Special Cases Hydrogen and Helium
Most abundant element in universe
Occurs as molecule of two atoms – H2
A lot of Earth’s H found in water (H20)
Is colorless, odorless, tasteless gas
Low density
Is a nonmetal
Forms compounds with many other elements
Not assigned to any group
Helium
Part of noble gases –but only has 2 electrons in outer shell
2nd most abundant element on Earth
Is rare due to atoms being so light they escape from the atmosphere
Is found where there is natural gas (mostly in Texas)
Is twice as dense as H and is nonflammable
Has lowest boiling point of any substance and does not freeze unless pressure is applied

18. Lab Activity
The Missing Person
See hand-out

19. Additional Activities
Video - The Periodic Table
Activity - Fabulous Periodic Eggs
Lab – Understanding and Using the Periodic Table
Activity - Element Scrabble
Worksheet – The Periodic Table
Element Cards
Web Quest

20. Credits Textbook – Science Explorer Grade 8 Prentice Hall
Textbook – Chemistry – Molecule, Matter, and Changes – Atkins, Peter and Jones, Loretta
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