The Periodic Table of Elements

1. The Periodic Table of Elements Ms. Williams 7th Grade Science Allen Middle School

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 (1887-1915) • 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. Remember rows fly across. • Group: a column of elements on a periodic table that share similar characteristic. Remember groups fall down.

7. More Vocabulary • 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 Coinage Metals • Group 11 Elements -Copper-Gold -Silver • These elements were often used by ancient civilizations to make coins.

19. The Lanthanides 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 powerplants. The Lanthanides and The Actinides

20. Let’s See What We Remember • What are rows on a periodic table called? • What are columns on a periodic table called? • Name the two divisions of the periodic table? • What can we learn from an element key? • How can scientist use the periodic table?

21. The End A ComicRelief Production