Clue 1
NOBLE LONER
The mystery element, which sits in the far right column of the periodic table, is one of the "noble gases." You can't see it--it's a colorless, odorless gas. And liker all noble gases, it's chemically inert, or doesn't combine with any other elements except in extreme cases. But don't be fooled by this loner. It makes up about 7 percent of all the atoms in the universe.
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CLUE 2
DIVE DEEP
Scuba divers who go deeper than 40 meters (130 feet) or stay underwater for long periods of time breathe a gas mixture of this element and two other nonmetal elements--oxygen and nitrogen--from their tanks. That's because this element helps prevent decompression sickness, or "the bends," a painful and potentially deadly condition that occurs when microscopic gas bubbles enter the bloodstream.
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CLUE 3
SQUEAK!
Inhale this element and you'll squeak like Bubbles the Powerpuff Girl. Sound waves in your mouth and throat travel two and a half times faster through this low-density (amount of mass in a given space) gas than through air. Faster sound waves have a higher frequency (number of vibrations in a given time), which we hear as a high-pitched squeak. But beware: You can pass out or suffocate breathing only this gas.
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CLUE 4
ROCKET SCIENCE
Without this element, Neil Armstrong and Buzz Aldrin couldn't have walked on the moon. After blasting off, astronauts use liquid-fuel rockets containing this element to navigate the spacecraft. This type of rocket helped safely land the Lunar Module on the moon's surface--and maneuver the space shuttles. The rocket is powered when the mystery gas squirts into the liquid-fuel tanks on board. The inert element doesn't react with the fuel, but it forces the liquid out of the tanks to burn in the rocket's engines.
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CLUE 5
SAVING AMERICA'S INDEPENDENCE
The ink dried in 1776. But because of this element, tourists in Washington, D.C., can still see our forefathers' signatures on the Declaration of Independence. Exposure to air damages the fragile document, so in 1951 it was sealed in a glass box filled with the mystery element. Unlike oxygen, this inert gas doesn't react with the paper or ink. But the element is so tiny--the second-smallest atom--that over time it's leaked through minuscule holes in the containers. The document is now being resealed in a box filled with another inert--but larger--element: argon.
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CLUE 6
AIR TIME
Converse once designed basketball shoes filled with this lightweight element to help players leap like the pros. The now-defunct sneakers had three gas-filled canisters in the heel of each shoe. Filled with just air, the canisters would weigh about 100 grams (3.5 ounces). Filled with the mystery gas, they weighed only 14 g (0.5 oz). But the tiny weight loss didn't really boost basketball players' scores.
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CLUE 7
FUTURE FUEL
This element may be the nonpolluting energy of the future. Scientists hope to use one form of the element in fusion (combining two atoms to form one new atom), a reaction that releases large amounts of energy. But even though it's the second most abundant element in the universe, Earth's supply will likely run out in less than 50 years. Miners may soon head to the moon, which has the useful form in its soil. "The moon has a thousand years worth of Earth's electrical energy needs," says Gerald Kulcinski of the University of Wisconsin.
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CLUE 8
HEAVY LIFTING
It's the power lifter of the periodic table. Although it has only 92 percent of the lifting ability of hydrogen--the only lighter element--the mystery gas is non-flammable and safer to use. Seven times lighter than air, its buoyant force hoists the 12,800-pound Goodyear Blimp. And every year, Macy's uses about 400,000 cubic feet of the gas to float giant cartoon characters in the Thanksgiving Day Parade.
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ANATOMY OF AN ELEMENT
X Atomic number
?? Element symbol
Name Element name
X.XXXX Average atomic mass
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 hence has a unique atomic number.
ATOMIC MASS equals the number of protons plus the number of neutrons found in a single atom of an element. The weight of an atom resides in its nucleus, which houses both protons and neutrons.
The periodic table is a systematic way to organize Earth's elements, substances that consists 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. Scientist have created elements with atomic numbers greater than 92--but they don't exist naturally.
IT'S YOUR CHOICE Test your chemistry IQ! Answer the following questions about elements and the periodic table.
1. Name the mystery element! --
2. Which element has 47 electrons orbiting its nucleus?
A. copper (Cu) B. cadmium (Cd) C. silver (Ag) D. tungsten (W)
3. The elements in the far right column of the periodic table are called:
A. alkali metals B. nonmetals C. metals D. noble gas
4. Inert elements:
A. combine only with nonmetals
B. don't combine with other elements except in extreme cases
C. combine with all elements
D. re alkali metals
5. Which of the following elements is the heaviest
A. lead (Pb) B. zirconium (Zr) C. radon (Rn) D. manganese (Mn)
6. What property increases from left to right in a period on the table?
A. atomic number B. atomic weight C. number of protons D. all of the above
EASY ORBIT: Atoms of the mystery element have two electrons orbiting a nucleus that contains two neutrons and two protons.
1. Helium 2. c 3. d 4. b 5. c 6. d
Did You Know?
* Helium balloons don't keep their shape as long as balloons that are filled with air because the tiny helium atoms readily escape through microscopic holes in the rubber.
* The name helium is derived from helios, the Greek word for sun. It's the only element to have been discovered on the sun before it was found on Earth. In 1868, astronomer Pierre Janssen detected a bright yellow line in the spectrum of light from the sun. Every element gives off a unique color when it's heated to a high temperature, and this color hadn't been identified yet. It was determined to be helium by astronomer Joseph Norman Lockyer and chemist Edward Frankland. Chemist Sir William Ramsey finally found helium on Earth 27 years later.
* Liquid helium is the only fluid that cannot be solidified by lowering its temperature; at normal pressures it remains a liquid to absolute zero.
Cross-Curricular Connection
Math: Helium gas can lift about 1 gram per liter. If the average party balloon holds 14 liters of gas, about how many would you need to lift off? (Hint: 1 kilogram = 2.2 pounds) For a related activity, turn to TE 5.
Critical Thinking:
In the future, fusion energy using helium atoms may be a way to produce electricity without polluting the atmosphere. But since there isn't enough helium on Earth to last very long, scientists think we should send miners to the moon, which has the useful form in its soil. Do you think it's a good idea to dig up the surface of the moon for helium? Why or why not?
For an interactive periodic table with basic information about all of the elements see: www.chemicalelements.com/
The Goodyear site has a detailed history of blimps. It includes a diagram of the blimp, descriptions of how each component works, and lots of pictures: www.goodyearblimp.com/
Scientists release helium filled balloons to monitor the weather and collect data about the atmosphere. This National Weather Service site has information about the balloons and how they are used: www.srh.noaa.gov/elp/kids/balloon.shtml
To test your knowledge of the symbols and names of the elements on the periodic table, play the FunBrain game: www.funbrain.com/periodic/
The University of Wisconsin Sea Grant site has information about scuba diving and decompression sickness. Includes experiments and quizzes: www.seagrant.wisc.edu/madisonjason11/diving.html