Chapter 2

Question 1

When an electron is moved further from the nucleus

a. its potential energy may change, depending on how the electron was moved
b. it loses potential energy
c. it gains potential energy
d. its potential energy is unchanged

Answer 1

C

Question 2

How many electrons does it take to fill the first electron shell of a carbon atom?

a. 4
b. 2
c. 1
d. 8

Answer 2

B

Question 3

How many covalent bonds do hydrogen atoms need to form with other atoms to complete their valence shell?

a. 3
b. 4
c. 1
d. 2

Answer 3

C

Question 4

When we write “O=O”, the double line represents

a. two ionic bonds between the oxygen atoms
b. two electrons shared by the oxygen atoms
c. two covalent bonds between the oxygen atoms
d. two protons shared by the oxygen atoms

Answer 4

C

Question 5

Nitrogen (N) is more electronegative than hydrogen (H). Which of the following statements is correct about ammonia (NH3)?

a. Each hydrogen atom has a slight negative charge.
b. Each hydrogen atom has a partial positive charge.
c. The nitrogen atom has a strong positive charge.
d. There are covalent bonds between the hydrogen atoms.

Answer 5

B

Question 6

How many covalent bonds do nitrogen atoms need to form with other atoms to complete their valence shell?

a. 3
b. 2
c. 4
d. 1

Answer 6

A

Question 7

How many covalent bonds do carbon atoms need to form with other atoms to complete their valence shell?

a. 4
b. 1
c. 2
d. 3

Answer 7

A

Question 8

Molecules are

a. two or more atoms joined by ionic bonds
b. two or more atoms joined by covalent bonds
c. two or more atoms joined by hydrogen bonds
d. all of these answers are correct

Answer 8

B

Question 9

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that

a. an electron may move to an electron shell closer to the nucleus.
b. the atom may become a radioactive isotope.
c. the atom would become a negatively charged ion, or anion.
d. an electron may move to an electron shell farther away from the nucleus

Answer 9

D

Question 10

Water is an example of

a. only a molecule
b. only a compound
c. both a compound and a molecule
d. neither a compound nor a molecule

Answer 10

C

Question 11

How many more electrons do oxygen atoms need to complete their valence shell?

a. 1
b. 4
c. 2
d. 6

Answer 11

C

Question 12

Depending on how far an electron is moved from the nucleus

a. you can decrease its potential energy by only certain amounts
b. you can decrease its potential energy by any amount
c. you can increase its potential energy by only certain amounts
d. you can increase its potential energy by any amount

Answer 12

C

Question 13

If you make a model of a methane (CH4) molecule, the overall shape of the molecule will most closely resemble

a. a straight line
b. a wide “V”
c. a pyramid
d. a square

Answer 13

C

Question 14

Which of the following statements regarding atomic particles is correct?

a. Electrons are negatively charged, protons are neutral and neutrons are neutral.
b. Electrons are negatively charged, protons are positively charged and neutrons are neutral.
c. Electrons are negatively charged, protons are positively charged and neutrons are positively charged.
d. Electrons are negatively charged, protons are positively charged and neutrons are negatively charged.

Answer 14

B

Question 15

Magnesium is an example of

a. an organic substance
b. an element
c. a molecule
d. a compound

Answer 15

B

Question 16

Electron shells

a. may have any average distance from the nucleus but may have only certain energy levels
b. may have only certain average distances from the nucleus but may have any energy level
c. may have only certain average distances from the nucleus and may have only certain energy levels
d. may have any average distance from the nucleus and any energy level

Answer 16

C

Question 17

Which types of chemical reactions occur faster at equilibrium, the formation of products from reactants or reactants from products?

a. Both reactions occur at the same rate.
b. It depends on the reaction in question.
c. The formation of products from reactants occurs at a faster rate.
d. The formation of reactants from products occurs at a faster rate.

Answer 17

A

Question 18

Oxygen gas (O2) is an example of

a. an anion
b. a molecule
c. a compound
d. an organic substance

Answer 18

B

Question 19

The bonds in a water molecule are

a. non-polar covalent bonds
b. polar covalent bonds
c. ionic bonds
d. hydrogen bonds

Answer 19

B

Question 20

The reactivity of an atom arises from

a. the potential energy of the valence shell
b. the difference in the potential energy of the valence and non-valence electron shells
c. the average distance of the outermost electron shell from the nucleus
d. the existence of unpaired electrons in the valence shell

Answer 20

D

Question 21

Which of the following do NOT comprise a significant fraction of the human body?

a. hydrogen
b. sodium
c. carbon
d. nitrogen

Answer 21

B

Question 22

Which of the following statements most accurately describes an electron orbital?

a. Electron orbitals describe the different paths that electrons follow around the nucleus.
b. An electron orbital is the three-dimensional space where an electron is found 90% of the time.
c. Electron orbitals may have any shape.
d. Only one electron may occupy each electron orbital.

Answer 22

B

Question 23

The further on average an electron is from the nucleus

a. the less highly charged it is
b. the greater its potential energy
c. the more highly charged it is
d. the lower its potential energy

Answer 23

B

Question 24

What is the maximum number of electrons in the 1s orbital of an atom?

a. 4.
b. 3.
c. 1.
d. 2.

Answer 24

D

Question 25

With regards to orbitals, which of the following statements is FALSE? a. An orbital can be depicted as a cloud where an electron may be located. b. An orbital is occupied by one or two electrons. c. An orbital is a region surrounding the nucleus where the probability of finding an electron is high. d. An orbital is a defined path that an electron follows as it orbits the nucleus.

Answer 25

D

Question 26

When a sodium atom and a chlorine atom interact to complete their valence shells Select one: a. an electron is transferred from sodium to chlorine, turning the sodium atom into an anion and the chlorine atom into an cation and allowing the two atoms to form an ionic bond b. an electron is transferred from sodium to chlorine, turning the sodium atom into a cation and the chlorine atom into an anion and allowing the two atoms to form an ionic bond c. they form 2 polar covalent bonds d. they form 1 polar covalent bond

Answer 26

B

Question 27

Why does the structure shown below fail to make sense chemically? H-C=C-H a. The two carbon atoms share more than 1 bond. b. Each hydrogen atom only has 1 covalent bond. c. Carbon is more electronegative than hydrogen and should thus remove electrons from hydrogen, rather than forming a covalent bond with hydrogen. d. Each carbon atom only has 3 covalent bonds.

Answer 27

D

Question 28

``` How many electrons do oxygen atoms have in their valence shell? Select one: a. 1 b. 4 c. 2 d. 6 ```

Answer 28

D

Question 29

A hydrogen atom can complete its valence shell by a. all of these answers are correct b. forming a covalent bond with a carbon atom c. transferring an electron to another atom d. forming a covalent bond with another hydrogen atom

Answer 29

A

Question 30

If atom “A” is more electronegative than atom “B”, than a. atom “A” will attract electrons more strongly than atom “B” b. atom “A” will remove electrons from atom “B” c. atom “A” has fewer electrons than atom “B” d. atom “A” will have a negative charge of -1

Answer 30

A

Question 31

``` Which of the following is not a compound? Select one: a. H2 b. CH4 c. H2O d. NaCl ```

Answer 31

A

Question 32

Which subatomic particles are directly involved in chemical reactions between atoms? a. nuclei b. neutrons c. electrons d. protons

Answer 32

C

Question 33

Atoms with incomplete valence shells may complete their shell by Select one: a. all three of the other answers are correct, depending on the atom in question b. transferring electrons to another atom c. transferring electrons from another atom d. sharing electrons with another atom

Answer 33

A

Question 34

How many electrons do hydrogen atoms have in their valence shell? a. 8 b. 4 c. 1 d. 2

Answer 34

C

Question 35

Electron shells Select one: a. may have only certain average distances from the nucleus but may have any energy level b. may have any average distance from the nucleus and any energy level c. may have only certain average distances from the nucleus and may have only certain energy levels d. may have any average distance from the nucleus but may have only certain energy levels

Answer 35

C

Question 36

Nitrogen (N) is more electronegative than hydrogen (H). Which of the following statements is correct about ammonia (NH3)? Select one: a. The nitrogen atom has a strong positive charge. b. There are covalent bonds between the hydrogen atoms. c. Each hydrogen atom has a partial positive charge. d. Each hydrogen atom has a slight negative charge.

Answer 36

C

Question 37

The number of electrons needed to fill the different electron shells is a. 2 in the 1st shell and 2 in the 2nd shell b. 2 in the 1st shell and 4 in the 2nd shell c. 4 in the 1st shell and 8 in the 2nd shell d. 2 in the 1st shell and, 8 in the 2nd shell

Answer 37

D