AnswersEO Night School Chemistry 7320AUnit Test

Unit Test — Unit test Answers

25 verified answers
1
Free Preview

Which reason best explains why metals are shiny?

A
because their valence electrons reflect light
B
because their valence electrons absorb light
C
because their valence electrons oscillate between bands
D
because their valence electrons move to higher energy levels
2
Free Preview

Which statement best describes the properties of metals?

A
They are shiny and bend without breaking.
B
They are dull and are good electrical insulators.
C
They conduct electricity well and are brittle.
D
They can be flattened and do not conduct heat well.
3

The incomplete table below shows selected characteristics of different types of bonds.RowBondCausePhysical property of compound1?Electron sharing among many atomsDuctile2?Electron sharing between two atomsBrittle3??BrittleWhat type of bond is most likely being represented in row 1?

A
ion-dipole
B
ionic
C
metallic
D
covalent
4

Which of the following compounds would be expected to have the strongest ionic bonds?

A
the compound that has the largest ions with the greatest charge
B
the compound that has the largest ions with the least charge
C
the compound that has the smallest ions with the greatest charge
D
the compound that has the smallest ions with the least charge
5

Lewis structures cannot

A
show the number of valence electrons.
B
show the location of bonds.
C
show the strength of bonds.
D
show how many bonds are present in a molecule.
6

How do ionic bonds affect the properties of ionic compounds?

A
The bonds weakly hold ions together, increasing the melting point.
B
The bonds strongly hold ions together, reducing the boiling point.
C
The bonds prevent ions from moving throughout the crystal, so a solid ionic compound is a poor conductor.
D
The bonds prevent electrons from moving throughout the crystal, so a solid ionic compound is a good conductor.
7

Among the intermolecular forces, which forces are typically the weakest?

A
dipole-dipole interactions
B
hydrogen bonds
C
dipole-induced dipole interactions
D
London dispersion forces
8

The table below shows the electronegativity values of various elements on the periodic table.ElectronegativitiesWhich pair of atoms would form a covalent bond ?

Question illustration
A
calcium (Ca) and bromine (Br)
B
rubidium (Rb) and sulfur (S)
C
cesium (Cs) and nitrogen (N)
D
oxygen (O) and chlorine (Cl)
9

The diagram below shows DNA molecules.What do the broken lines connected to hydrogen atoms represent in this diagram?

Question illustration
A
the weakest intermolecular forces
B
the weakest intramolecular forces
C
the strongest intermolecular forces
D
the strongest intramolecular forces
10

An element has six valence electrons available for bonding. Which group of the periodic table does this element most likely belong to?

A
group 2
B
group 4
C
group 16
D
group 18
11

When applied to a dish, soap makes grease soluble in water. Which explanation correctly supports the role of intermolecular forces in this common observation?

A
The nonpolar end of a soap molecule attaches itself to grease.
B
The nonpolar end of a soap molecule attaches itself to water.
C
The polar soap molecule attaches itself to the dish.
D
The polar soap molecule attaches itself to a nonpolar soap molecule.
12

Which is the Lewis structure for H3PO4?

A
mc013-1.jpg
Option A
B
A central upper P is single bonded left, right, above, and below to upper Os. The O above the P is single bonded to upper H on the left and the right, and has two electron dots above it. The O below the P is single bonded to an H below, and has pairs of electron dots to the left and right.
Option B
C
A central upper P is double bonded to an O above, and single-bonded to an upper O single-bonded to an upper H to the left and the right. The O above the P has three pairs of electron dots, to the left, above, and to the right; the O's to the right and left have pairs of dots above and below.
Option C
D
A central upper P is bonded to an upper H above, an upper O below, and upper O's bonded to upper H's to the left and the right. The O below the P has three pairs of electron dots, to the left, right, and below; the other two O's have pairs of dots above and below. A central upper P is double bonded to an O above, and single-bonded to an upper O single-bonded to an upper H to the left and the right. The O above the P has three pairs of electron dots, to the left, above, and to the right; the O's to the right and left have pairs of dots above and below.
Option D
13

Based on its location in the periodic table, what can most likely be predicted about phosphorus?

A
It has three valence electrons.
B
It has four valence electrons.
C
It has five valence electrons.
D
It has six valence electrons.
14

Which statement best describes London dispersion forces?

A
repulsive intramolecular forces
B
attractive intramolecular forces
C
attractive intermolecular forces
D
repulsive intermolecular forces
15

The incomplete table below shows selected properties of compounds that have ionic, covalent, or metallic bonds.RowSubstanceType of bondLikely property1KCl?Brittle2?CovalentDoes not conduct electricity3??MalleableWhich substance would be most suitable for row 3?

A
sodium chloride (NaCl)
B
silver (Ag)
C
nitrogen (N)
Option C
D
propane (CH)
Option D
16

Which compound has the highest melting point?

A
Al2(CO3)3
B
C12H22O11
C
C8H18
D
H2O
17

Which of these is a property of a substance that is composed of atoms that are held together by ionic bonds?

A
It can be shaped into wires.
B
It has a low melting point.
C
It conducts electricity when in solid form.
D
It conducts electricity when it is dissolved in water.
18

Which statement best describes the effect of low ionization energies and low electronegativities on metallic bonding?

A
The valence electrons are easily delocalized.
B
The valence electrons stay in a single orbital.
C
The valence electrons break free of the crystals.
D
The valence electrons move closer to the nuclei.
19

Which statement is true about ionic compounds?

A
Solid ionic compounds are good conductors of electricity.
B
Ionic compounds have varying solubilities in water.
C
Ionic compounds have very low melting points.
D
Ionic compounds are very easy to bend.
20

Which element is likely to be the most brittle?

A
selenium
B
cobalt
C
platinum
D
zinc

Did you find these answers helpful?

More from this Course

Quiz
25 verified answers

Unit Test

Quiz
20 verified answers

Unit Test

Quiz
10 verified answers

Covalent Bonding