1. Notes on the Periodic Table

2. Antoine Lavoisier
1790’s
made a list of all the known elements; there were 23
By the 1870’s, there were 70 known elements
A system of organization was needed

3. Dimitri Medeleev
Was given credit for the first periodic table even though John Newland also developed an organizational system.
Based on increasing atomic mass and similar chemical properties

4. Dimitri Medeleev Predicted the existence of unknown elements
Some elements were out of order

5. Henry Mosely
Measured the frequency of the X-rays given off by different elements.
Each element gave a different frequency
Frequency was mathematically related to the position of the element in the Periodic Table
He could actually measure atomic number

6. Henry Mosely
Re- designed the periodic table to show an increase in atomic number.
Periodic Table now follows the periodic law.

7. Parts of the Periodic Table
Staircase- separates metals and non-metals
Metals
Non-Metals

8. Metals Ductile Good conductors of heat and electricity
Able to be drawn into wire
Able to be pounded into sheets
Good conductors of heat and electricity

9. Metals
Are likely to lose electrons, forming positive ions called cations.

10. Click on metal to watch a cool you tube video!
Alkali Metals
Click on metal to watch a cool you tube video!
Most reactive group of metal elements
All contain 1 valence electron
Lithium Metal

11. Alkaline Earth Metals Also a very reactive metal group.
Not as reactive as Alkali metals.

12. Metalloids Separate the metals from the non-metals
Found along the staircase
Have properties of both metals and non-metals
Are 7 of them
Used in computer chips
Used in solar cells

13. Non- Metals
Are brittle, poor conductors of heat and electricity and many are gases at room temperature.
Are likely to gain electrons to form negatively charged ions or anions.
S2-

14. Halogens Most reactive group of non-metals Found in Group 17 or VII A
Fluorine is the queen.
Chlorine, Bromine and Iodine at room temperature. Fluorine could not be included due to its high reactivity.

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Noble or Inert Gases
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Least reactive/ most stable group on the periodic table
Each element has 8 valence electrons with the exception of He, which only has 2

16. Transition and Inner Transition Metals
d sublevels
f sublevels

17. Period vs. Group Group Period Also known as a family
Have similar chemical properties because they all have the same number of valence electrons.
Valence electrons occupy different principal energy levels.
Horizontal rows on table
Have principal quantum numbers of 1-7
Elements in a period have different properties because they all have different numbers of valence electrons.
All valence electrons occupy the same principal energy level.

18. Numbering the Periodic Table
Old Way
New Way
A groups and B groups
B groups were the transition elements
A groups were the rest
Used Roman Numerals to indicate the number of valence electrons for the A groups
Valence electrons are important for bonding /chemical properties
All elements want 8 valence electrons
Numbering the periodic table groups from 1-18
Makes all periodic tables uniform
Slightly more difficult to determine valence electrons. (must subtract 10 from groups 13-18)