Unit 3 Test

 

 

†††††††††† 1.†††††††††† A particle of matter contains 6 protons, 7 neutrons, and 6 electrons.This particle must be a

A

neutral nitrogen atom

C

positively charged carbon ion

B

neutral carbon atom

D

positively charged nitrogen ion

 

 

†††††††††† 2.†††††††††† The mass number of an atom is always equal to the total number of its

A

protons only

C

electrons plus protons

B

electrons only

D

protons plus neutrons

 

 

†††††††††† 3.†††††††††† What is the approximate mass of an electron?

A

1 atomic mass unit

C

1/1836 of a proton

B

1/12 of a C-12 atom

D

1836/1837 of a proton

 

 

†††††††††† 4.†††††††††† What is the molar mass of calcium nitrate, Ca(NO3)2?

A

164 g/mole

C

102 g/mole

B

150. g/mole

D

70.0 g/mole

 

 

†††††††††† 5.†††††††††† What is the total number of atoms in 1 mole of calcium?

A

1

C

6.02 x 1023

B

40

D

40(6.02 x 1023)

 

 

†††††††††† 6.†††††††††† What is the mass (in grams) of 3.0 x 1023 molecules of CO2?

A

22 g

B

44 g

C

66 g

D

88 g

 

 

†††††††††† 7.†††††††††† The major portion of an atomís mass consists of

A

electrons and protons

C

neutrons and positrons

B

electrons and neutrons

D

neutrons and protons

 

 

†††††††††† 8.†††††††††† Which atom contains exactly 15 protons?

A

phosphorus - 32

C

oxygen - 15

B

sulfur - 32

D

nitrogen - 15

 

 

†††††††††† 9.†††††††††† Which symbols represent atoms that are isotopes of each other?

A

14C and 14N

B

131I and 131I

C

16O and 18O

D

222Rn and 222Ra

 

 

†††††††††† 10.†††††††† Which pair of atoms contains the same number of neutrons?

A

11H and 32He

B

31H and 32He

C

21H and 42He

D

31H and 42He

 

 

†††††††††† 11.†††††††† The atomic theory proposed by Dalton

A

has been totally discarded

C

has been accepted unchanged to the present day

B

has been expanded and modified

D

has been found to be false

 

 

†††††††††† 12.†††††††† As the average atomic masses of the elements on the Periodic Table increase, the number of atoms in 1 mole of each element

A

decreases

B

increases

C

remains the same

 

 

†††††††††† 13.†††††††† Daltonís atomic theory helped to explain the law of conservation of mass because it stated that atoms

A

could not combine

C

all had the same mass

B

could not be created or destroyed

D

were invisible

 

 

†††††††††† 14.†††††††† Element X has two naturally-occurring isotopes.If the percent abundance of 85X is 72.0% and the percent abundance of 87X is 28.0 %, the average atomic mass of element X is equal to

A

(72.0 x 85) x (28.0 + 87)

C

(0.72 x 87) + (0.28 x 85)

B

(72.0 - 85) x (28.0 + 87)

D

(0.72 x 85) + (0.28 x 87)

 

 

†††††††††† 15.†††††††† How many neutrons does fluorine - 17 have in its nucleus?

A

9

B

8

C

7

D

6

 

 

†††††††††† 16.†††††††† Most of the volume of an atom is made up of the

A

nucleus

B

electron cloud

C

neutrons

D

protons

 

 

†††††††††† 17.†††††††† The atomic number of neon is 10.The atomic number of calcium is 20.Compared with a mole of neon, a mole of calcium contains

A

twice as many atoms

C

an equal number of atoms

B

half as many atoms

D

20 times as many atoms

 

 

†††††††††† 18.†††††††† The nucleus of an atom has all of the following characteristics EXCEPT that it

A

is positively charged

C

contains nearly all of the atomís mass

B

is very dense

D

contains nearly all of the atomís volume

 

 

†††††††††† 19.†††††††† Zinc - 66 (atomic number 30) has

A

30 neutrons

B

35 neutrons

C

36 neutrons

D

96 neutrons

 

 

†††††††††† 20.†††††††† The atomic number of oxygen, 8, indicates that there are eight

A

protons in the nucleus of an oxygen atom

B

oxygen isotopes

C

neutrons outside the oxygen atomís nucleus

D

energy levels in the oxygen atomís nucleus

 

 

†††††††††† 21.†††††††† An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons.Its mass number is

A

13

B

14

C

27

D

40

 

 

†††††††††† 22.†††††††† The mass of 2.50 moles of calcium atoms is approximately

A

10.0 g

B

100. g

C

42.5 g

D

250. g

 

 

†††††††††† 23.†††††††† What is the correct number of atomic particles in a neutral atom with an atomic number of 53 and a mass number of 127?

A

protons = 53, electrons = 127, neutrons = 127

B

protons = 53, electrons = 74, neutrons = 74

C

protons = 127, electrons = 127, neutrons = 74

D

protons = 53, electrons = 53, neutrons = 74

 

 

†††††††††† 24.†††††††† According to the law of conservation of mass, when sodium, hydrogen, and oxygen react to form a compound, the mass of the compound is ___ the sum of the masses of the individual elements.

A

equal to

C

less than

B

greater than

D

either greater than or less than

 

 

†††††††††† 25.†††††††† An ion with 5 protons, 6 neutrons, and a charge of +3 has an atomic number of

A

5

B

6

C

8

D

11

 

 

Matching

 

Match the scientist to his contribution to the development of the atomic theory.

A

Bohr

D

Rutherford

B

Chadwick

E

Thomson

C

Dalton

 

 

 

†††††††††† 26.†††††††† discovered the neutron†††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††† B

 

†††††††††† 27.†††††††† discovered the electron using a cathode ray tube†††††††††††††††††††††††††† E

 

†††††††††† 28.†††††††† postulated that electrons travel around the nucleus in orbits†††††††††† A

 

†††††††††† 29.†††††††† first published atomic theory;law of conservation of mass††††††††††† C

 

30.                  discovered the nucleus using the gold foil experiment††††††††††††††††††† D

 

 

Back to the Unit 3 Old Test Page

Back to the Unit 3 Page

Back to the Main Page