1. The Periodic Table of Elements

2. Dmitri Mendeleev (1834-1907) Russian Chemist
Published the first version of the period table in 1869
Arranged elements according to increasing atomic mass
His periodic table had gaps

3. Henry Moseley ( )
Made improvements to Mendeleev’s Periodic Table
Arranged elements by atomic number instead of mass
Realized that there were undiscovered elements

4. The Modern Periodic Table

5. The Element Key
The Element Key provides lots of important information

6. Time for Vocabulary Period: A row of elements on a periodic table.
Group: a column of elements on a periodic table that share similar characteristics.

7. Classifications
Metal: an element that has luster and is a good conductor of heat and electricity.
Nonmetal: elements that are usually gases or brittle solids at room temperature and are poor conductors of heat and electricity.
Metalloid: an element that shares some properties with metals and some with nonmetals.

8. Representative Elements
Groups 1-2 & 13-18
Alkali Metals
Alkaline Earth Metals
The Boron Family
The Carbon Group
The Nitrogen Group
The Oxygen Group
The Halogens
The Noble Gases

9. The Alkali Metals Group 1 Elements: -Lithium -Rubidium -Sodium -Cesium
-Potassium -Francium
Silvery Solids
Low Densities
Low Melting Points

10. The Alkaline Earth Metals
The Group 2 Elements
-Beryllium -Magnesium
-Calcium -Strontium
-Barium Radium
Denser than Alkali Metals
Higher melting points than Alkali Metals

11. The Boron Family Group 13 Elements -Boron -Aluminum -Gallium -Indium
-Thallium
All are metals except Boron
Aluminum is the most common metal in the Earth’s crust.

12. The Carbon Group Group 14 Elements -Carbon -Silicon -Germanium -Tin
-Lead
Silicon is used to make semiconductors for computers and other electronics .
Diamond and Graphite are two forms of carbon.

13. The Nitrogen Group Group 15 Elements -Nitrogen -Phosphorus
-Arsenic -Antimony
-Bismuth
Almost 80% of the air we breathe is nitrogen.
Phosphorus is an essential ingredient in healthy teeth and bones.

14. The Oxygen Group Group 16 Elements -Oxygen -Sulfur
-Selenium -Tellurium
-Polonium
About 20% of the Earth’s atmosphere is oxygen.
Sulfuric acid is one the most used chemicals in the world

15. The Halogens Group 17 Elements -Fluorine -Chlorine -Bromine -Iodine
-Astatine
The Halogens form salts with the alkali metals.
Fluorine is an active ingredient in toothpaste.

16. The Noble Gases Group 18 Elements -Helium -Neon -Argon -Krypton
-Xenon -Radon
Helium is used to fill balloons.
Neon signs contain noble gases.

17. Transition Elements Groups 3-12 All transition elements are metals.
Group 11 (The Coinage Metals)
The Lanthanides
The Actinides

18. The Lanthanides and The Actinides
Soft metals that can be cut with a knife.
Were once called rare earth metals.
Glass used in computer and TV screens contain Yttirum and Europium.
The Actinides
All actinides are radioactive.
Thorium, Proactinium and Uranium are the only actinides found naturally on earth.
Plutonium is used to fuel nuclear power plants.

19. Periodic Trends

20. Periods The elements in each period have the same number of shells
1st Period = 1 Shell
2nd Period = 2 Shells
3rd Period = 3 Shells
4th Period = 4 Shells

21. Groups Group 8 = 8 electrons Group 1 = 1 electron
Except for He, it has 2 electrons
Group 2 = 2 electrons
3, 4, 5, 6, 7
Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.
The electrons in the outer shell are called “valence electrons”

22. Transition Metals
Transition Metals have slightly different rules for shells and valence electrons.
This is something you will learn about in High School Chemistry.

23. Determine the number of shells and the number of valence electrons for:
Carbon
Sodium
Neon
Helium

24. Determine the number of shells and the number of valence electrons for:
Carbon - C
2nd Period = 2 shells
4th Group =
4 valence
electrons

25. Determine the number of shells and the number of valence electrons for:
Sodium - Na
3rd Period = 3 shells
1st Group =
1 valence
electron

26. Write your answers on your handout.Ne
Name the element.
Number of shells ?
Valence electrons ?
Neon
2nd Period = 2 shells
8th Group = 8 valence
electrons

27. Write your answers on your handout.He
Name the element.
Number of shells ?
Valence electrons ?
Helium
1st Period = 1 shell
8th Group = 2 valence
electrons
Helium is the exception in Group 8.
Since it has just one shell, that shell can only fit 2 electrons instead of 8.
It is in this group because all the elements have a full outer shell.