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Chemical Elements and The Periodic Table

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What is an element?

An element is….

- a chemical substance that cannot be changed into simpler substances under normal laboratory conditions.

- a chemical substance from which all other substances are made.

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Interesting Uses of Chemical Elements

Barium is used in fireworks to give the fireworks its green color.

Mercury is the fluid in thermometers.

Celcium is used in atomic clocks.

Arsenic is used in weed killers, pesticides and poisons.

Osmium is used in the form of osmium tetroxide in fingerprint powders.

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Terms to Know…

Chemical SymbolA chemical symbol is an abbreviation of the name of a

chemical element, such as N for nitrogen or Fe for iron. Chemical symbols can be one or two letters.

Some other examples of symbols are:Ni – Nickel Rh – Rhodium Co - CobaltZn – Zinc Ba – Barium Cu - CopperAs – Arsenic Ne – Neon Y – YttriumImportant: The lst letter of the abbreviation is always a

capital letter. The second letter is always lowercase.

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Terms to Know…

AtomAn atom is the smallest particle possessing the properties of

an element.ElectronAn electron is a particle possessing negative electrical

charge; Electrons are found within atoms.ProtonA proton is a particle possessing positive electrical charge;

protons are found in the nucleus of all atoms.NeutronA neutron is a particle possessing no electrical charge;

neutrons are found in the nucleus of most atoms.

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More Terms to Know…

IsotopesIsotopes are atoms of the same element with differing numbers of

neutrons.

Atomic MassAtomic mass of a particular atom of an element is the weighted

average of the masses of the isotopes of an element.

Atomic NumberThe atomic number is the number of protons in an atom; it

distinguishes atoms of different element.

Mass number

The mass number is the total number of protons and neutrons in the nucleus of an atom.

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What is The Periodic Table?

The Periodic Table is an arrangement of chemical elements that is the principal tool for thinking about elements and the properties associated with them.

- The rows in a table are arranged by increasing atomic number of the elements.

- The columns are arranged in groups or “families” of elements having similar chemical characteristics.

It is important to remember that…- rows go across - also called horizontal.- columns go up and down – also called vertical.

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These are two reasons why The Periodic Table is important.

The Periodic Table organizes lots of information about all the known elements easily.

It is also the most useful tool to a chemist AND CHEMISTRY STUDENTS!

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Dimitri Mendeleev is known as “The Father of the Periodic Table!”

When Mendeleeev placed elements in his

Periodic Table, he had all elements arranged in order of increasing relative atomic weight.

However, in the modern Periodic Table, the elements are placed in order of the number of protons in the nucleus.

Other organizational systems exist, but Mendeleev’s table is the most widely used.

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About the current Periodic Table

The chemical elements are put in rows by increasing ATOMIC NUMBER!!

The horizontal rows (going across) are called periods and are labeled from 1 to 7.

The vertical columns (going up and down) are called groups (families) and are labeled from 1 to 18.

On the periodic table, metals fill the left, center, and part of the right-hand side of the chart. Thus it should not come as a surprise that most elements (87, in fact) are metals.

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Metals & Nonmetals

Pure metals are typically shiny and malleable.ex. gold, silver,copper, tin, zinc, lead.

Nonmetals in their elemental form are usually gases or solids.ex. Boron, carbon as diamond, yellow sulfur.

Nonmetallic elements combine with metallic elements to form salts.

Nonmetallic elements combine with each other to form compounds.

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Answer the questions on your worksheet about The Periodic Table.

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Click on the link below.

Chemical Elements

Choose one of the chemical elements and click on it. Answer the questions on your worksheet about the element you chose.

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Periods

PERIODS

Even though they skip some squares in between, all of the rows go left to right. When you look at a periodic table, each of the rows is considered to be a different period. In the periodic table, elements have something in common if they are in the same row. All of the elements in a period have the same number of atomic orbitals. Every element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons. It goes down the periodic table like that. At this time, the maximum number of electron orbitals or electron shells for any element is seven.

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Groups/Families

GROUPS/FAMILIES

Now you know about periods. The periodic table has a special name for its columns, too. When a column goes from top to bottom, it's called a group. The elements in a group have the same number of electrons in their outer orbital. Every element in the first column (group one) has one electron in its outer shell. Every element on the second column (group two) has two electrons in the outer shell. As you keep counting the columns, you'll know how many electrons are in the outer shell. There are some exceptions to the order when you look at the transition elements, but you get the general idea.

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Two at the Top

TWO AT THE TOP

Hydrogen and helium are special elements.

To scientists, hydrogen is sometimes missing an electron, and sometimes it has an extra.

Helium is different from all of the other elements. It can only have two electrons in its outer shell. Even though it only has two, it is still grouped with elements that have eight.

The elements in the center section are called transition elements. They have special electron rules.

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Hydrogen

Hydrogen in a solid acts as a metal.

Hydrogen on earth is a diatomic, reactive gas.

Hydrogen was involved in the explosion of the Hindenberg.

Hydrogen is promising as an alternative fuel source for automobiles

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Group/Family names going across are…

Column1 - Alkali MetalsColumn 2 - Alkaline Earth MetalsColumns 3 -12 - Transitional MetalsColumn 13 – BoronColumn 14 – CarbonColumn 15 - NitrogenColumn 16 - OxygenColumn 17 - Halogens Column 18 - Noble Gases

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Now, let’s look at the 18 groups/families

Remember, groups/families…- Go across- There are 18 groups/families

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Alkali Metals

1st column on the periodic table (Group 1) not including hydrogen.

Very reactive metals, always combined with something else in nature (like in salt).

Soft enough to cut with a butter knife

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Alkaline Earth Metals

Second column on the periodic table. (Group 2)

Reactive metals that are always combined with nonmetals in nature.

Several of these elements are important mineral nutrients (such as Mg and Ca

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Transition Metals – The dip!

Elements in groups 3-12

Less reactive harder metals

Includes metals used in jewelry and construction.

Metals used “as metal.”

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Boron Family

Elements in group 13 Aluminum metal was

once rare and expensive, not a “disposable metal.”

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Carbon Family

Elements in group 14 Contains elements

important to life and computers.

Carbon is the basis for an entire branch of chemistry.

Silicon and Germanium are important semiconductors.

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Nitrogen Family Elements in group 15 Nitrogen makes up over

¾ of the atmosphere. Nitrogen and

phosphorus are both important in living things.

Most of the world’s nitrogen is not available to living things.

The red stuff on the tip of matches is phosphorus.

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Oxygen Family or Chalcogens

Elements in group 16 Oxygen is necessary for

respiration. Many things that stink,

contain sulfur (rotten eggs, garlic, skunks,etc.)

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Halogens

Elements in group 17 Very reactive, volatile,

diatomic, nonmetals Always found combined

with other element in nature .

Used as disinfectants and to strengthen teeth.

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The Noble Gases

Elements in group 18 VERY nonreactive,

monatomic gases Used in lighted “neon”

signs Used in blimps to fix the

Hindenberg problem. Have a full valence

shell.

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Now, go to the book cart, choose one of the following elements, and write 5 facts about your element.

Radioactive elements Gold BromineManganese Zinc IodineCadmium Uranium NickelHydrogen and the Noble gases Mercury ActiniumSodium Aluminum CobaltPotassium Carbon FranciumIron Silicon PoloniumChromium Nitrogen PotassiumCalcium Oxygen ZirconiumMagnesium Sulfur TinCopper Chlorine ZincSilver Fluorine FluorineNickel Tungsten Boron

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Works Cited

Bentor, Yinon. Chemical Element.com. Sep. 5, 2006 <http://www.chemicalelements.com>.

“Chemical Element.” Encyclopaedia Britannica Online School Edition, 2006. Mayde Creek High

School Library. Houston, TX. 30 August 2006. http://www,school.eb.com.

Heikkinen, Henry, ed. Chemistry in the Community. New York: W.H. Freeman, 2002.

“Periodic Table.” 28 August 2006. www.nebo.edu.

“Periodic Table.” World of Physics. Science Resource Center. Thomson Gale. Mayde Creek

High School Library, Houston, TX. 31 August 2006. http://galenet.galegroup.com.

Wilbraham, Antony C., ed. Chemistry. Needham, MA: Prentice Hall, 2002.

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The End!Compiled by Mrs. Greene

Mayde Creek High School Librarian

September 1, 2006