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

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

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

The Modern Periodic Table

The Element Key The Element Key provides lots of important information

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.

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.

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

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

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

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.

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.

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.

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

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.

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

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

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

The Lanthanides and The Actinides 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 power plants.

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?

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