1) How many electrons are shared in a single covalent bond?

A) 3 B) 2 C) 4 D) 8 E) 1

1)

2) How many electrons are shared in a double covalent bond?

A) 2 B) 8 C) 6 D) 3 E) 4

2)

3) How many unshared pairs of electrons does the nitrogen atom in ammonia possess?

A) 1 B) 2 C) 4 D) 5 E) 3

3)

4) What is the total number of covalent bonds normally associated with a single carbon atom in a

compound.

A) 2 B) 3 C) 4 D) 8 E) 1

4)

5) How many covalent bonds are there in a covalently bonded molecule containing 1 phosphorus

atom and 3 chlorine atoms?

A) 1 B) 6 C) 4 D) 2 E) 3

5)

6) How do atoms achieve noble-gas electron configurations in single covalent bonds?

A) Two atoms share one electron.

B) Two atoms share two pairs of electrons.

C) Two atoms share two electrons.

D) One atom completely loses two electrons to the other atom in the bond.

6)

7) What is shown by the structural formula of a molecule or polyatomic ion?

A) the number of metallic bonds B) the number of ionic bonds

C) the arrangement of bonded atoms D) the shapes of molecular orbitals

7)

8) Which elements can form diatomic molecules joined by a single covalent bond?

A) hydrogen, halogens, and members of the oxygen group

B) hydrogen and the halogens only

C) halogens only

D) hydrogen only

E) halogens and members of the oxygen group only

8)

9) Which of the following elements can form diatomic molecules held together by triple covalent

bonds?

A) fluorine B) hydrogen C) nitrogen D) carbon E) oxygen

9)

10) A covalent bond in which each atom contributes two electrons is a _____.

A) polar covalent bond B) double covalent bond

C) coordinate covalent bond D) four electron bond

10)

11) A molecule with a single covalent bond is _____.

A) CO2 B) N2 C)CO D) Cl2

11)

12) Which of the following electron configurations gives the correct arrangement of the four valence

electrons of the carbon atom in the molecule methane (CH4)?

A) 2s12p13s1 B) 2s12p3 C) 2s22p2 D) 2s12p23s1

12)

13) When one atom contributes both bonding electrons in a single covalent bond, the bond is called

a(n) _____.

A) ionic covalent bond

B) unequal covalent bond

C) coordinate covalent bond

D) ordinary covalent bond

E) one-sided covalent bond

13)

14) When H+ forms a bond with H2O to form the hydronium ion H3O+, this bond is called a

coordinate covalent bond because _____.

A) the electrons are equally shared

B) it forms an especially strong bond

C) both bonding electrons come from the oxygen atom

D) the oxygen no longer has eight valence electrons

14)

15) Which of the following is a true statement concerning the resonant molecule dinitrogen

tetraoxide?

A) It breaks down readily because resonant molecules are inherently unstable.

B) It alternates between its resonance forms.

C) It has a structure that is intermediate between its drawn resonance forms.

D) It remains in one resonance form most of the time.

15)

16) Substances in which all of the electrons are paired are said to be _____.

A) diamagnetic B) electromagnetic C) paramagnetic D) ferromagnetic

16)

17) Which of the following types of magnetism is the strongest?

A) ferromagnetic B) paramagnetic C) diamagnetic

17)

18) In which of the following compounds is the octet expanded to include 12 electrons.

A) SO

2-

3 B) SO

2-

4 C) SO3 D) SCl6 E)H2S

18)

19) Which of the following pairs of elements can be joined by a covalent bond?

A) Mg and C B) Na and C C) Li and Cl D) N and C

19)

20) Which of the following bonds is the least reactive?

20)

21) How many electrons can occupy a single molecular orbital?

A) 0 B) 2 C) 1 D) 8 E) 4

21)

22) Molecular orbital theory is based upon which of the following models of the atom?

A) classical mechanical model B) quantum mechanical model

C) Bohr model D) Democritus model

22)

23) Which of the following types of orbital has the highest energy?

A) atomic orbital B) bonding orbital C) antibonding orbital

23)

24) Where are the electrons most probably located in a molecular bonding orbital?

A) between the two atomic nuclei

B) in circular orbits around each nucleus

C) in stationary positions between the two atomic nuclei

D) anywhere in the orbital

24)

25) A molecular antibonding orbital is unfavorable to bonding between atoms because _____.

A) electrons are not located between nuclei and, therefore, repulsive forces are increased

B) electrons are located between nuclei and, therefore, repulsive forces are increased

C) electrons are located between nuclei and, therefore, repulsive forces are decreased

D) electrons are not located between nuclei and, therefore, repulsive forces are decreased

25)

26) Which of the following bond types is normally the weakest?

A) pi bond formed by the overlap of two p orbitals

B) sigma bond formed by the overlap of two s orbitals

C) sigma bond formed by the overlap of two p orbitals

D) sigma bond formed by the overlap of one s and one p orbital

26)

27) What causes water molecules to have a bent shape, according to VSEPR theory?

A) repulsive forces between specific electrons

B) the unusual location of the free electrons

C) interaction between the fixed orbitals of the unshared pairs of oxygen

D) ionic attraction and repulsion

27)

28) Which of the following structures is characterized by a bond angle of 107@?

A) bent structure B) linear structure

C) pyramidal structure D) tetrahedral structure

28)

29) The shape of the carbon tetrachloride molecule is called _____.

A) planar B) tetrahedral C) four-cornered D) square

29)

30) What type of hybrid orbital exists in the methane molecule?

A) sp B) sp3 C) sp2 D) sp3d2

30)

31) How many hybrid orbitals surround a carbon atom that participates in only one double bond?

A) 1 B) 4 C) 2 D) 0 E) 3

31)

32) What type of hybridization occurs in the orbitals of a carbon atom participating in a triple bond

with another carbon atom?

A) sp B) sp3 C) sp2

32)

33) Which of the following covalent bonds is the most polar?

33)

34) Which of the following pairs of elements can be joined by a polar bond?

A) N and C B) Na and C C) C and C

34)

35) In an electric field, which region of the water molecule is attracted to the positive pole?

A) No part of the water molecule is attracted to the positive pole.

B) the oxygen region of the molecule

C) the hydrogen region of the molecule

35)

36) What is thought to cause the dispersion forces?

A) attraction between ions

B) motion of electrons

C) differences in electronegativity

D) attraction between polar molecules

E) sharing of electron pairs

36)

37) What causes dipole interactions?

A) attraction between polar molecules

B) attraction between ions

C) sharing of electron pairs

D) motion of electrons

E) bonding of a covalently-bonded hydrogen to an unshared electron pair

37)

38) Why is hydrogen-bonding only possible with hydrogen?

A) because hydrogen is the only atom that is the same size as an oxygen atom

B) because hydrogen is the only atom whose nucleus is not shielded by electrons when it is

involved in a covalent bond

C) because hydrogen has the highest electronegativity of any element in the periodic table

38)

39) Which of the following causes the boiling point of HF to be much higher than that of HCl or HBr?

A) hydrogen bonds B) van der Waals forces

C) coordinate covalent bonds D) covalent bonds

39)

40) Which type of solid has the highest melting point?

A) nonmetallic solid B) ionic solid C) network solid D) metal

40)

41) Calculate the total bond energy in one mole of methyl alcohol, CH3OH. (Assume that the

total bond energy in a molecule is the sum of the individual bond energies.)

Bond Energy (kJ/mol)

41)

1) Answer: B

2) Answer: E

3) Answer: A

4) Answer: C

5) Answer: E

6) Answer: C

7) Answer: C

8) Answer: B

9) Answer: C

10) Answer: B

11) Answer: D

12) Answer: B

13) Answer: C

14) Answer: C

15) Answer: C

16) Answer: A

17) Answer: A

18) Answer: D

19) Answer: D

20) Answer: B

21) Answer: B

22) Answer: B

23) Answer: C

24) Answer: A

25) Answer: A

26) Answer: A

27) Answer: A

28) Answer: C

29) Answer: B

30) Answer: B

31) Answer: E

32) Answer: A

33) Answer: D

34) Answer: A

35) Answer: B

36) Answer: B

37) Answer: A

38) Answer: B

39) Answer: A

40) Answer: C

Total bond energy = 1999 kJ