Covalent Bonding

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Name:

Covalent Bonding

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n)

a.	dipole.	c.	chemical bond.
b.	Lewis structure.	d.	London force.

The electrons involved in the formation of a chemical bond are called

a.	dipoles.	c.	Lewis electrons.
b.	s electrons.	d.	valence electrons.

As atoms bond with each other, they

a.	increase their potential energy, thus creating less-stable arrangements of matter.
b.	decrease their potential energy, thus creating less-stable arrangements of matter.
c.	increase their potential energy, thus creating more-stable arrangements of matter.
d.	decrease their potential energy, thus creating more-stable arrangements of matter.

The chemical bond formed when two atoms share electrons is called a(n)

a.	ionic bond.	c.	Lewis structure.
b.	orbital bond.	d.	covalent bond.

If two covalently bonded atoms are identical, the bond is

a.	nonpolar covalent.	c.	nonionic.
b.	polar covalent.	d.	coordinate covalent.

If the atoms that share electrons have an unequal attraction for the electrons, the bond is called

a.	nonpolar.	c.	ionic.
b.	polar.	d.	dipolar.

Most chemical bonds are

a.	purely ionic.	c.	partly ionic and partly covalent.
b.	purely covalent.	d.	metallic.

Nonpolar covalent bonds are not common because

a.	one atom usually attracts electrons more strongly than the other.
b.	ions always form when atoms join.
c.	the electrons usually remain equally distant from both atoms.
d.	dipoles are rare in nature.

Bonds that are between 5% and 50% ionic are considered

a.	ionic.	c.	polar covalent.
b.	pure covalent.	d.	nonpolar covalent.

10.

Bonds that are more than 50% ionic are considered

a.	polyatomic.	c.	ionic.
b.	polar covalent.	d.	nonpolar covalent.

11.

A bond that is less than 5% ionic is considered

a.	polar covalent.	c.	nonpolar covalent.
b.	ionic.	d.	metallic.

12.

In which of these compounds is the bond between the atoms NOT a nonpolar covalent bond?

a.	Cl₂	c.	HCl
b.	H₂	d.	O₂

13.

A neutral group of atoms held together by covalent bonds is a

a.	molecular formula.	c.	compound.
b.	chemical formula.	d.	molecule.

14.

A ____ shows the types and numbers of atoms joined in a single molecule of a molecular compound.

a.	molecular formula	c.	covalent bond
b.	chemical formula	d.	ionic bond

15.

In a molecule of fluorine, the two shared electrons give each fluorine atom ____ electron(s) in the outer energy level.

a.	1	c.	8
b.	2	d.	32

16.

The octet rule states that chemical compounds tend to form so that each atom has an octet of electrons in

a.	its highest occupied energy level.	c.	its d orbitals.
b.	the 1s orbital.	d.	its p orbitals.

17.

In drawing a Lewis structure, each nonmetal atom except hydrogen should be surrounded by

a.	2 electrons.	c.	8 electrons.
b.	4 electrons.	d.	10 electrons.

18.

In drawing a Lewis structure, the central atom is the

a.	atom with the greatest mass.	c.	atom with the fewest electrons.
b.	atom with the highest atomic number.	d.	least electronegative atom.

19.

To draw a Lewis structure, one must know the

a.	number of valence electrons in each atom.
b.	atomic mass of each atom.
c.	bond length of each atom.
d.	ionization energy of each atom.

20.

The substance whose Lewis structure shows three covalent bonds is

a.	H₂O.	c.	NH₃.
b.	CH₂Cl₂.	d.	CCl₄.

21.

What is the Lewis structure for hydrogen chloride, HCl?

a.	A	c.	C
b.	B	d.	D

22.

What is the Lewis structure for carbon tetraiodide, which contains one carbon atom and four iodine atoms?

a.	A	c.	C
b.	B	d.	D

23.

A shorthand representation of the composition of a substance using atomic symbols and numerical subscripts is called a(n)

a.	Lewis structure.	c.	polyatomic ion.
b.	chemical formula.	d.	multiple bond.

24.

A formula that shows the types and numbers of atoms combined in a single molecule is called a(n)

a.	molecular formula.	c.	Lewis structure.
b.	ionic formula.	d.	covalent formula.

25.

Compared with ionic compounds, molecular compounds

a.	have higher boiling points.	c.	have lower melting points.
b.	are brittle.	d.	are harder.

26.

A compound that vaporizes readily at room temperature is most likely to be a(n)

a.	molecular compound.	c.	metal.
b.	ionic compound.	d.	brittle compound.

27.

The properties of both ionic and molecular compounds are related to the

a.	lattice energies of the compounds.
b.	strengths of attraction between the particles in the compounds.
c.	number of covalent bonds each contains.
d.	mobile electrons that they contain.

28.

In the electron-sea model of a metallic bond,

a.	electrons are stationary.
b.	electrons are bonded to particular positive ions.
c.	some electrons are valence electrons and some are not.
d.	mobile electrons are shared by all the atoms.

29.

The electron-sea model of bonding represents

a.	covalent bonding.	c.	ionic bonding.
b.	metallic bonding.	d.	hydrogen bonding.

30.

To appear shiny, a material must be able to

a.	form crystals.
b.	absorb and re-emit light of many wavelengths.
c.	absorb light and change it all to heat.
d.	change light to electricity.

31.

The shiny appearance of a metal is most closely related to the metal's

a.	electron sea.	c.	brittle crystalline structure.
b.	covalent bonds.	d.	positive ions.

32.

Because metallic bonds permit one plane of ions to slide past another without breaking bonds, metals are

a.	brittle.	c.	nonreflective.
b.	malleable.	d.	poor conductors of electricity.

33.

Malleability and ductility are characteristic of substances with

a.	covalent bonds.	c.	Lewis structures.
b.	ionic bonds.	d.	metallic bonds.

34.

The model for predicting the shape of a molecule that is based on the repulsion of electrons for each other is called

a.	hybridization.	c.	London force model.
b.	Lewis structure.	d.	VSEPR theory.

35.

According to VSEPR theory, an AB₂ molecule is

a.	trigonal planar.	c.	linear.
b.	tetrahedral.	d.	octahedral.

36.

VSEPR theory is a model for predicting

a.	the strength of metallic bonds.	c.	lattice energy values.
b.	the shape of molecules.	d.	ionization energy.

37.

The concept that electrostatic repulsion between electron pairs surrounding an atom causes these pairs to be separated as far as possible is the foundation of

a.	VSEPR theory.	c.	the electron-sea model.
b.	the hybridization model.	d.	Lewis theory.

38.

According to VSEPR theory, the shape of an AB₃ molecule is

a.	trigonal planar.	c.	linear.
b.	tetrahedral.	d.	bent.

39.

According to VSEPR theory, the structure of the ammonia molecule, NH₃, is

a.	linear.	c.	pyramidal.
b.	bent.	d.	tetrahedral.

40.

Use VSEPR theory to predict the shape of the hydrogen chloride molecule, HCl.

a.	tetrahedral	c.	bent
b.	linear	d.	trigonal planar

41.

Use VSEPR theory to predict the shape of the magnesium hydride molecule, MgH₂.

a.	tetrahedral	c.	bent
b.	linear	d.	octahedral

42.

Use VSEPR theory to predict the shape of the carbon tetraiodide molecule, CI₄.

a.	tetrahedral	c.	bent
b.	linear	d.	trigonal planar

43.

Use VSEPR theory to predict the shape of the hydrogen sulfide molecule, H₂S.

a.	tetrahedral	c.	bent
b.	linear	d.	octahedral

44.

Use VSEPR theory to predict the shape of carbon dioxide, CO₂.

a.	tetrahedral	c.	bent
b.	linear	d.	octahedral

45.

A polar molecule contains

a.	ions.
b.	a region of positive charge and a region of negative charge.
c.	only London forces.
d.	no bonds.