Elements

The Periodic Table of Elements

Why is the Periodic Table important to me?

• The periodic table is the most useful tool to a chemist.

• You get to use it on every test.

• It organizes lots of information about all the known elements.

Pre-Periodic Table Chemistry…

• …was a mess!!!• No organization of

elements.• Imagine going to a

grocery store with no organization!!

• Difficult to find information.

• Chemistry didn’t make sense.

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

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

The Modern Periodic Table

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 & 13-18• Alkali Metals• Alkaline Earth Metals• The Boron Family• The Carbon Group• The Nitrogen Group• The Oxygen Group• The Halogens• The Noble Gases

Hydrogen

• Hydrogen belongs to a family of its own.

• Hydrogen is a diatomic, reactive gas.

• Hydrogen was involved in the explosion of the Hindenberg.

• Hydrogen is promising as an alternative fuel source for automobiles

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?

The End

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