Name That Element!

This alkaline earth metal is the fifth most plentiful element in Earth’s crust—the layer of rock that forms Earth’s outer surface. It’s most commonly found in compounds. For example, it often chemically combines with carbonate ions—positively charged molecules made up of one carbon (C) atom and three oxygen (O) atoms. This compound gets heated and squeezed deep underground to form marble. Workers used this type of stone to construct the outside of the Taj Mahal, a famous mausoleum in India. Got it already? Score 100 points. Otherwise, read clue #2.

The mystery element is the fifth most common one in Earth’s crust—the rock layer that forms Earth’s outer surface. This element is also an alkaline earth metal. It’s mostly found in compounds. For example, it often combines with carbonate ions. These molecules have a positive charge. They’re made up of one carbon (C) atom and three oxygen (O) atoms. The compound gets heated and squeezed underground to form marble. Workers used this stone to build the Taj Mahal, a famous tomb in India. Got it already? Score 100 points. Otherwise, read clue #2.

This element is found in the same group (column) on the periodic table as beryllium (Be). All of the elements in this group fluoresce, or glow, under ultraviolet (UV) light by absorbing these invisible energy waves and releasing visible light people can see. The mystery element combines with other elements, like fluorine (F) and zinc (Zn), to form rocks that glow red, yellow, green, and even purple under UV light. Know the element? Score 80 points. If not, try clue #3.

This element and beryllium (Be) are in the same group (column) on the periodic table. All of the elements in this group fluoresce. That means they glow under ultraviolet (UV) light. They soak up these invisible energy waves and release them as light people can see. The mystery element combines with other elements, like fluorine (F), to form rocks. Under UV light, these rocks glow red, green, and even purple. Know the element? Score 80 points. If not, try clue #3.

Seawater contains dissolved particles of the carbonate form of the mystery element. Shellfish, such as oysters and mussels, use this compound to make pearls. Sometimes a harmful parasite can sneak inside a marine animal’s shell. The shellfish coats the intruder in layer upon layer of the carbonate form of the mystery element. Over time, this traps the parasite inside a hard, shiny sphere—a pearl. People have valued pearls for centuries because they are both beautiful and rare. Figured it out? Score 60 points. No luck? See clue #4.

Seawater contains tiny particles of the carbonate form of this element. Shellfish, such as oysters and mussels, use this compound to make pearls. Sometimes a harmful parasite can sneak inside these animals’ shells. The shellfish covers the intruder with layers of the carbonate compound. The parasite is trapped! Over time, the layers form a hard, shiny ball—a pearl. People have prized pearls for hundreds of years. That’s because they’re both beautiful and rare. Figured it out? Score 60 points. No luck? See clue #4.

Without the mystery element—found in the same period (row) as krypton (Kr)—your body wouldn’t be able to function. You need this element to have strong bones and teeth. It’s also used to send messages through your nervous system, to help blood clot, and to allow your muscles to contract. To get this essential nutrient, you need to eat food that contains the mystery element, like milk and other dairy products. Guessed the element? Score 40 points. No? Check out clue #5.

Your body wouldn’t work without this element, which is in the same period (row) as krypton (Kr). You need the mystery element for strong bones and teeth. It sends messages through your nervous system and helps blood clot. It also allows your muscles to contract. To get this important nutrient, you must eat food that contains it. Milk and other dairy products are good examples. Guessed the element? Score 40 points. No? Check out clue #5.

This element is the basis for the spiky rock formations found in caves. Dissolved in water, the mystery element drips into a cave. As the water evaporates, or changes from a liquid to a gas, a hardened form of the element is left behind. The result is stalactites that hang from the ceilings of a cave and stalagmites that rise from its floors. These formations grow about 16 cubic centimeters (1 cubic inch)—roughly the size of a gumball—every 100 years. Did you solve the mystery? Score 20 points.

The spiky rock formations in caves are made of this element. After the mystery element dissolves in water, it drips into a cave. The water evaporates, or changes from a liquid to a gas. It leaves behind a hardened form of the element. The result is stalactites that hang from cave ceilings and stalagmites that rise from cave floors. These formations grow about 16 cubic centimeters (one cubic inch) every 100 years. That’s about the size of a gumball. Did you solve the mystery? Score 20 points. 

The periodic table is a systematic way to organize Earth's elements—substances that each consist of only one kind of atom. Today, there are 118 known chemical elements.

Elements on the periodic table are arranged by their atomic nubmers in ascending order. Hydrogen (H), for example, has an atomic number of 1 and is the lightest known natural element.

Scientists have created elements with atomic numbers greater than 92, but they don't exist naturally.

The periodic table is a systematic way to organize Earth's elements—substances that each consist of only one kind of atom. Today, there are 118 known chemical elements.

Elements on the periodic table are arranged by their atomic nubmers in ascending order. Hydrogen (H), for example, has an atomic number of 1 and is the lightest known natural element.

Scientists have created elements with atomic numbers greater than 92, but they don't exist naturally.

Use the periodic table and what you learned about the mystery element to answer the following questions.

1. What is the atomic number of krypton (Kr)?

A. 10

B. 18

C. 36

D. 86

2. Alkaline earth metals are found in group __________.

A. 1

B. 2

C. 3

D. 4

3. Which of the following is NOT a transition metal?

A. gold (Au)

B. zinc (Zn)

C. manganese (Mn)

D. magnesium (Mg)

4. Which of the following elements is in the same period as molybdenum (Mo)?

A. xenon (Xe)

B. chlorine (Cl)

C. mercury (Hg)

D. arsenic (As)

5. Two or more elements that are chemically combined form a(n) __________.

A. ion

B. alloy

C. mixture

D. compound

Use the periodic table and what you learned about the mystery element to answer the following questions.

1. What is the atomic number of krypton (Kr)?

A. 10   

B. 18    

C. 36

D. 86

2. Alkaline earth metals are found in group __________.

A. 1   

B. 2    

C. 3

D. 4

3. Which of the following is NOT a transition metal?

A. gold (Au)

B. zinc (Zn)

C. manganese (Mn)

D. magnesium (Mg)

4. Which of the following elements is in the same period as molybdenum (Mo)?

A. xenon (Xe)

B. chlorine (Cl)

C. mercury (Hg)

D. arsenic (As)

5. Two or more elements that are chemically combined form a(n) __________.

A. ion

B. alloy

C. mixture

D. compound