1st Quarter Reviewer: S.Y. 2011-2012 Ver 2

Time Frame: 10 mins

Source: http://www.avon-chemistry.com/nuclear_practice.htm

Hi everyone! This is a quick test for chapters 3 and 4 of our textbook. Have fun.

MULTIPLE CHOICE:

1.      Cathode rays are:

A

negatively charged particles

B

positively charged particles

C

nuclei of a helium atom

D

fast moving neutrons

2.     The neutral atoms of all of the isotopes of the same element have:

A

the same mass numbers

B

equal numbers of neutrons

C

the same number of electrons

D

different number of protons

3.      Which statement is true about an isotope?

A

There can be more than one type of isotope for an element.

B

All isotopes for an element has the same number of protons and the same mass number.

C

Isotopes can have different numbers of protons.

D

All isotopes are not radioactive.

4.      How many electrons are in an oxygen atom?
 

A

2

B

6

C

8

D

10

5.  Copper has an atomic mass of 63.5 grams per mole. Why is the atomic mass NOT a whole number?
 

A

All copper atoms have identical chemical properties.

B

The fractional number results from the fact that protons and neutrons have different masses.

C

Every copper atom has an atomic mass of 63.5 amu.

D

There are at least two naturally occurring isotopes of copper.

6.      Which symbol represents an atom that contains the largest number of neutrons?

 

A

U-235

B

Pa-231

C

Np-239

D

Pu-240

E

U-239

7. The number of protons in fluorine-23 is 

A

6

B

8

C

9

D

14

E

23

8. Find the average mass of an element if the relative amounts are as follows:
   Isotopic Mass: Percentage:
   75 amu ----------- 2.3%
   77 amu ----------- 15.7 %
   78 amu ----------- 4.5 %
   80 amu ----------- 7.1 %
   81 amu ----------- 70.4 % 

A

77.25 amu

B

78.01 amu

C

79.09 amu

D

80.03 amu

E

81.09 amu

9. Which of the following is NOT true about chemical reactions? 

A

After a chemical reaction, the protons and neutrons within the atom have not changed.

B

After a chemical reaction, there are new bonds formed while others bonds were broken.

C

After a chemical reaction, an electron may enter the nucleus and change a proton to a neutron.

D

After a chemical reaction, the boiling points and melting points of the new products are different.

10. How many protons, neutrons, and electrons are in one atom of Pb-212 (atomic number 82)?

A

212 p+, 82 n0, 212 e-

B

82 p+, 212 n0, 212 e-

C

82 p+, 212 n0, 82 e-

D

82 p+, 82 n0, 212 e-

E

none of the above are correct

Did you have fun? Here are the answers!

1. a

2. c

3. a

4. c

5. d

6. e

7. d

8. d

9. c

10. e