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The Periodic Table

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Chapter 12

CRCT Preparation


Chapter 12 CRCT Preparation

1. What does the number at the top of the square above tell you about carbon?

A A carbon nucleus has 6 protons.

B Carbon has an average atomic mass of 6.

C Carbon has 6 isotopes.

D A carbon atom has 6 electrons in its outermost energy level.



2. Approximately how many elements are in the periodic table?

A between 75 and 100

B between 100 and 125

C between 125 and 150

D more than 150


3. Alberto has an element that is a shiny, brittle solid that conducts electric current. The element most likely belongs to which class of elements?

A halogens

B metals

C nonmetals

D metalloids



4. In what order are the regions arranged on the periodic table when you read it from left to right?

A noble gases, metals, nonmetals, metalloids

B metalloids, metals, nonmetals, noble gases

C metals, metalloids, nonmetals, noble gases

D nonmetals, noble gases, metals, metalloids



5. Fluorine, chlorine, bromine, iodine, and astatine make up Group 17, the halogens. Why are these elements grouped together?

A They are all very reactive nonmetals that have similar chemical properties.

B They are all nonreactive gases that have similar physical properties.

C Their atoms all have 8 electrons in their outer energy levels.

D They all have the same atomic number.




6. Which of the following best describes the properties of metals?

A hard, brittle, and nonconductive

B liquid, dark, and conductive

C shiny, malleable, and conductive

D soft, oily, and very reactive


7. Which of the following statements about cobalt (Co) and nickel (Ni) is true?


C Cobalt atoms have more electrons than nickel atoms do.

D Cobalt and nickel belong to the same group on the periodic table.

A Nickel has a greater average atomic mass than cobalt does.

B Nickel atoms have more protons than cobalt atoms do.



8. Which of the following statements about a group of elements is true?

A Atoms of the elements have the same number of neutrons.

B Atoms of the elements have the same atomic number.

C The elements have similar properties.

D The elements have the same average atomic mass.


9. What is the purpose of the zigzag line on the right side of the periodic table?

A It divides the metals and nonmetals and shows where the metalloids are.

B It indicates a group of elements that have the same chemical properties.

C It connects the elements in the table that have the same atomic number.

D It marks the border between the alkali metals and the transition metals.



10. In Mendeleev’s periodic table, the element iodine (I) came before tellurium (Te). He arranged the elements by atomic weight. Later, Henry Moseley revised the table to place iodine after tellurium. Explain the basis for Moseley’s revision to the periodic table.




10. Answer - Full-credit answers should include the following:

Moseley’s version of the periodic table is based on atomic number, not atomic mass. Some elements have higher atomic masses than the following element that has a higher atomic number. Therefore, some elements were rearranged when atomic numbers were discovered and used to organize the periodic table.


11. Sodium and potassium are members of the alkali metal group. What properties do sodium and potassium share with each other and with the other members of the alkali metal group? Describe at least four properties.



11. Answer - Full-credit answers should include at least four of the following points:

• Members of the alkali metals are all metals and therefore are shiny and are good conductors.

• Alkali metals are soft and can be cut with a knife.

• Atoms of alkali metals have one electron in their outermost energy level.

• Alkali metals have low densities.

• Alkali metals are very reactive.

• Alkali metals are silver in color.


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