Name that element! which element on the periodic table makes ultra light tennis rackets, brews up decaf coffee, and is the most important element for life on Earth? Follow these eight clues to find out. Then turn the page to test your chem IQ.

(CLUE 1)

AIRHEAD

Like all elements, this is rarely found in nature as single atoms, or the basic building blocks of matter. Instead, it forms molecules, two or more atoms joined together by a chemical bond. In Earth's atmosphere, the mystery element bonds with oxygen, a member of the same period, or row, on the periodic table.

GOT IT ALREADY? SCORE 100 POINTS. IF NOT, READ CLUE #2.

(CLUE 2)

GENE MACHINE

This element is the primary ingredient for all I life on Earth. It needs four additional electrons (negatively charged particles) to be stable; so it binds with up to four other atoms--including itself--to share their electrons. This helps it form chains of atoms that make DNA (chemical that carries hereditary information). Hint: When it gains four electrons, this element has the same number of electrons as neon.

NABBED THE ANSWER? SCORE 80 POINTS. STILL GUESSING? TAKE THE NEST CLUE.

(CLUE 3)

BUZZ OFF

This element takes the buzz out of coffee. When coffee passes through a filter made with this element, caffeine molecules stick to it. "There's an attraction between [the mystery element's] electrons and the caffeine molecules," says Kurt Dyck, engineer at Swiss Water Company. The filter absorbs caffeine and the rest of the liquid escapes. Voila, decaf coffee!

GAME OVER ALREADY? SCORE 60 POINTS. STILL PLAYING? CHECK OUT CLUE #4.

(CLUE 4)

TENNIS PRO

Andy Roddick scores big with tennis rackets made from this element. When atoms of this nonmetal line up in chains, they form fibers used to make rackets that are feather-light and stronger than steel. "[This element] makes rackets twice as stiff and twice as light as most of the metals on the periodic chart," says Bill Severa, director of technology for Wilson Sporting Goods.

NAME IT NOW? SCORE 40 POINTS. OTHERWISE, READ ON.

(CLUE 5)

NOODLE KNOCKER

Some dieters steer clear of this element. That's because it's a key component of carbohydrate molecules, or "carbs." Foods such as pasta, bread, and veggies contain carbs, which your body breaks down into sugar to burn for energy. But while overeating can lead to weight gain, a lack of carbs can deprive your body of essential nutrients. "It's good to have some carbohydrates as part of a balanced diet," says James BeMiller, a food scientist at Purdue University.

HIT ON THE ANSWER? SCORE 20 POINTS. IF NOT, KEEP TRYING!

(CLUE 6)

DOODLE TOOL

Students everywhere use this element to scribble notes and take tests. A pencil's "lead" is actually graphite, a pure form of this element. In graphite, atoms of the mystery element bind together in loose sheets making it one of Earth's softest minerals. Hint: The element lead is in the same group (column) on the periodic table as the mystery element.

SCORE 10 POINTS IF YOU NAME THE ELEMENT WITH THE HELP OF SIX CLUES. STILL GUESSING? READ ON.

(CLUE 7)

SPARKLER

Extreme temperature and pressure hundreds of miles below Earth's surface turn this element into dazzling gemstones. A diamond forms when atoms of this element squeeze together at 400[degrees]C (752[degrees]F) and under more than 400,000 pounds per square inch of pressure (force applied over an area). Because the atoms pack together so tightly under these conditions, they're tough to break apart--making diamonds the hardest material on Earth.

GUESS THE ELEMENT? SCORE 5 POINTS. IF NOT, TRY YOUR LAST CLUE.

(CLUE 8)

BREATH TEST

Take a deep breath. Inside your lungs, the mystery element combines with two atoms of oxygen to form a gas that you exhale, along with water molecules. In the winter, the water in your breath freezes to form vapor you can see while this element disappears into the atmosphere.

1. h 2. e 3. f 4. c 5. b 6. g 7. a 8. d

ANATOMY OF AN ELEMENT

ATOMIC NUMBER equals the number of protons (positively charged particles) in an atom's nucleus, or center. Every element contains a different number of protons, and so has a unique atomic number. In an atom, the number of protons and the number of electrons (negatively charged particles) are equal.

ATOMIC MASS equals the number of protons plus the number of neutrons (uncharged particles) found in a single atom of an element. The atom's mass is in its nucleus, which houses both protons and neutrons.

The PERIODIC TABLE

The periodic table is a systematic way to organize Earth's elements, substances that consist of atoms of only one kind. Today, there are 112 known and named chemical elements. Elements are arranged according to their increasing atomic number. Hydrogen (H), for example, has an atomic number of 1 and is the lightest known natural element on Earth. Scientists have created elements with atomic numbers greater than 92--but they don't exist naturally. Some scientists think they may have created elements heavier than 112, but until an element is confirmed by two different labs, it isn't listed on the periodic table.

IT'S YOUR CHOICE

Test your chemistry Ill! Answer the following questions about elements and the periodic table.

1. Name that element! --

2. A molecule is

A two or more atoms joined together by a chemical bond.

Answer

1.carbon 2. a 3. c 4. b 5. b 6. c

DID YOU KNOW?

* Popular demand for diamonds has spurred a large interest in producing artificial diamonds. "Fake diamonds" can be made by subjecting graphite to very high temperatures and pressures to simulate the natural processes taking place within Earth. The first artificial diamond was created in 1954 when a scientist subjected black carbon powder to pressures of 50,000 atmospheres (1 atmosphere = 14.7 pounds per square inch) for 16 hours!

CRITICAL THINKING:

* There is a growing trend in "low-carb" diets. But some critics fear that eating unbalanced meals could harm the body. First, study what a low-carb diet calls for. Then, discuss what food choices one should include to satisfy both the diet and the body's nutritional needs.

CROSS-CURRICULAR CONNECTIONS:

HISTORY: Research and then create a timeline on the history of pencil-making.

RESOURCES

* Grolier search term: Periodic Table of Elements

* For some basic background information on carbon, visit: http://education.jlab.org/itselemental/ele006.html

* Check out the different ways used to decaffeinate coffee: www.coffeeresearch.org/science/decaffeination.htm

B the basic building block of matter.

C two or more elements found in the same period, or row.

D the structure that is formed when an atom is heated to roughly 400[degrees]C (752[degrees]F).

3. Which of the following elements is a nonmetal?

A Niobium (Nb)

B Terbium (Tb)

C Bromine (Br)

D Strontium (Sr)

4. All the elements in a -- have similar characteristics, and are called a group.

A diagonal line

B column

C row

D periodic table

5. Which element is not found in group 14, the same group as lead?

A Tin (Sn)

B Arsenic (As)

C Germanium (Ge)

D Silicon (Si)

6. Which of the following is found in nature as a solid?

A Krypton (Kr)

B Mercury (Hg)

C Carbon (C)

D Oxygen (0)

DIRECTIONS: Match the word(s) in the left column with the correct phrase in the right column.

-- 1. atoms        a. uncharged particles
-- 2. molecules    b. chemical that carries hereditary information
-- 3. period       c. negatively charged particles
-- 4. electrons    d. positively charged particles
-- 5. DNA          e. two or more atoms joined together by a chemical
                      bond
-- 6. group        f. row on the periodic table
-- 7. neutrons     g. column on the periodic table
-- 8. protons      h. basic building blocks of matter