Chemistry Principles and Practice

Daniel L. Reger, Scott R. Goode, David W. Ball

Chapter 2

Atoms, Molecules, and lons - all with Video Answers

Educators

Chapter Questions

Problem 1

How does Dalton's atomic theory explain each of the following facts?
(a) A sample of pure $\mathrm{NaCl}$ (table salt) obtained from a mine in the United States contains sodium and chlorine in the same ratio as $\mathrm{NaCl}$ obtained from a mine in France.
(b) The mass of the hydrogen peroxide molecule, $\mathrm{H}_{2} \mathrm{O}_{2}$ equals the sum of the masses of the hydrogen, $\mathrm{H}_{2}$, and oxygen, $\mathrm{O}_{2},$ molecules from which it is formed.

Natalie Johns

Natalie Johns

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Problem 2

State how Dalton's atomic theory explains
(a) the law of conservation of mass.
(b) the law of constant composition.

Natalie Johns

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Problem 3

Compare and contrast the terms atom, element, molecule, and compound. Give an example of each. Some of your examples will fit more than one term, so clarify which term fits each example.

Natalie Johns

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Problem 4

Compare the masses and charges of the three major particles that make up atoms.

Natalie Johns

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Problem 5

Describe the experimental setup and results of the Rutherford experiment.

Crystal Wang

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Problem 6

How does the nuclear model of the atom explain the results of the Rutherford experiment?

Crystal Wang

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Problem 7

If aluminum foil had been used in the Rutherford experiment in place of gold foil, how might the outcome have differed?

Crystal Wang

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Problem 8

Describe the arrangement of protons, neutrons, and electrons in an atom.

Natalie Johns

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Problem 9

Define the following terms.
(a) atomic number
(b) mass number
(c) isotope

Natalie Johns

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Problem 10

What is the relationship between each of the following quantities and the numbers of the subatomic particles found in an atom?
(a) atomic number
(b) mass number
(c) symbol for element

Natalie Johns

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Problem 11

A mass spectrometer determines isotopic masses to eight or nine significant digits. What limits the atomic mass of carbon to only five significant digits?

Crystal Wang

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Problem 12

Explain the difference in the meanings of $4 \mathrm{P}$ and $\mathrm{P}_{4}$

Natalie Johns

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Problem 13

Explain the difference in the meanings of $8 \mathrm{~S}$ and $\mathrm{S}_{8}$.

Natalie Johns

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Problem 14

Methane, $\mathrm{CH}_{4}$, is the principal component of natural gas. Interpret the molecular formula of this compound in words.

Natalie Johns

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Problem 15

Dinitrogen tetroxide is a component of smog. Give the molecular formula of this gaseous compound, and interpret the formula in words.

Natalie Johns

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Problem 16

Carbon monoxide, $\mathrm{CO},$ is a molecular compound, whereas cesium bromide, $\mathrm{CsBr}$, is ionic. Explain the difference in the meanings of these two formulas.

Natalie Johns

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Problem 17

Sulfur dioxide, $\mathrm{SO}_{2}$, is a molecular compound that contributes to acid rain, and $\mathrm{CaCO}_{3}$ is an ionic compound that can neutralize acid rain. Explain the difference in the meanings of these two formulas.

Natalie Johns

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Problem 18

The names of acids formed from oxygen containing polyatomic anions are related to the name of the anion. How are the names of the anions modified to obtain the names of the acids?

Natalie Johns

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Problem 19

Does the name nitrogen oxide correctly apply to the compound NO? Explain why or why not.

Natalie Johns

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Problem 20

What is missing from the name chromium cbloride for the compound $\mathrm{CrCl}_{3}$ ?

Natalie Johns

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Problem 21

Describe the types of elements that generally combine to form ionic compounds and the types that combine to form molecular compounds.

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Problem 22

How do the properties of ionic compounds differ from those of molecular compounds?

Amy Jiang

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Problem 23

Explain why most ionic compounds are hard solids at room temperature, whereas most small molecular substances, such as $\mathrm{H}_{2} \mathrm{O}$ and $\mathrm{O}_{2}$, are liquids or gases.

Natalie Johns

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Problem 24

A chemist received a white crystalline solid to identify. When she heated the solid to $350^{\circ} \mathrm{C}$, it did not melt. The solid dissolved in water to give a solution that conducted electricity. Based on this information, what might the chemist conclude about the solid? Explain why.

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Problem 25

$\mathrm{NaCl}$ is said to dissociate in water. Draw a picture of this process.

Natalie Johns

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Problem 26

Explain on an atomic level why molten ionic compounds conduct electricity, whereas molten molecular compounds do not.

Crystal Wang

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Problem 27

Define group and period.

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Problem 28

Name and give the symbols for two elements that
(a) are metals.
(b) are nonmetals.
(c) are metalloids.
(d) consist of diatomic molecules.

Ronald Prasad

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Problem 29

Give the complete symbol $\left({ }_{Z}^{A} \mathrm{X}\right)$, including atomic number and mass number, of (a) a chlorine atom with 20 neutrons, and (b) a calcium atom with 20 neutrons.

Natalie Johns

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Problem 30

Give the complete symbol $\left({ }_{z}^{A} X\right)$, including atomic number and mass number, of (a) a nickel atom with 31 neutrons, and (b) a tungsten atom with 110 neutrons.

Natalie Johns

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Problem 31

Write the symbol that describes each of the following isotopes.
(a) an atom that contains 7 protons and 8 neutrons
(b) an atom that contains 31 protons and 39 neutrons
(c) an atom that contains 18 protons and 22 neutrons

Natalie Johns

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Problem 32

Write the symbol that describes each of the following isotopes.
(a) an atom that contains 5 protons and 6 neutrons
(b) an atom that contains 25 protons and 30 neutrons
(c) an atom that contains 14 protons and 14 neutrons

Natalie Johns

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Problem 33

Give the numbers of protons and neutrons $1 n$
(a) ${ }_{33}^{79} \mathrm{As}$
(b) $51 \mathrm{~V}$
23
(c) ${ }_{52}^{128} \mathrm{Te}$

Natalie Johns

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Problem 34

Give the numbers of protons and neutrons in
(a) ${ }_{16}^{32} \mathrm{~S}$
(b) ${ }_{12}^{24} \mathrm{Mg}$
(c) ${ }_{17}^{37} \mathrm{Cl}$

Natalie Johns

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Problem 35

Write the atomic symbol for the element whose monatomic ion has a $2+$ charge, has 14 more neutrons than electrons, and has a mass number of 88 .

Natalie Johns

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Problem 36

Write the atomic symbol for the element whose monatomic ion has a 2 - charge, has 20 more neutrons than electrons, and has a mass number of 126 .

Natalie Johns

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Problem 37

Write the symbol for the ion with
(a) 8 protons, 10 electrons, and 8 neutrons.
(b) 34 protons, 36 electrons, and 45 neutrons.
(c) 28 protons, 26 electrons, and 31 neutrons.

Natalie Johns

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Problem 38

Write the symbol for the ion with
(a) 4 protons, 2 electrons, and 5 neutrons.
(b) 32 protons, 30 electrons, and 40 neutrons.
(c) 35 protons, 36 electrons, and 44 neutrons.

Natalie Johns

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Problem 39

Write the symbol for the atom or ion of the species that contains
(a) 12 protons, 13 neutrons, and 10 electrons.
(b) 13 protons, 14 neutrons, and 10 electrons.
(c) 14 protons, 15 neutrons, and 14 electrons.
(d) 35 protons, 44 neutrons, and 36 electrons.

Natalie Johns

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Problem 40

Write the symbol for the atom or ion of the species that contains
(a) 23 protons, 28 neutrons, and 20 electrons.
(b) 53 protons, 74 neutrons, and 54 electrons.
(c) 44 protons, 58 neutrons, and 41 electrons.
(d) 15 protons, 16 neutrons, and 15 electrons.

Natalie Johns

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Problem 41

Given the partial information in each column of the following table, fill in the blanks. $\begin{array}{lcccc}\text { Symbol } & - & & 40 & \mathrm{Ca}^{2+} & & - & \\ \text { Atomic number } & 11 & - & - & - \\ \text { Mass number } & - & - & 81 & - \\ \text { Charge } & - & - & 1- & 2- \\ \text { Number of protons } & - & - & 35 & 52 \\ \text { Number of electrons } & 10 & - & - & - \\ \text { Number of neutrons } & 12 & - & - & 76\end{array}$ $-$

Crystal Wang

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Problem 42

Complete the table below. If necessary, use the periodic table. \begin{tabular}{ccccc} Symbol & Charge & Number of Protons & Number of Neutrons & Number of Electrons \\ \hline$-$ & 0 & 9 & 10 & $-$ \\ \hline${ }^{31} \mathrm{P}$ & 0 & $-$ & 16 & $-$ \\
$-$ & $3+$ & 27 & 30 & $-$ \\ $-$ & $-$ & 16 & 16 & 18 \end{tabular}

Crystal Wang

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Problem 43

Data obtained with a mass spectrometer show that, in a sample of an element, $60.11 \%$ of the atoms have masses of $68.926 \mathrm{u}$, whereas the remaining $39.89 \%$ of the atoms have masses of 70.926 u. Calculate the atomic mass of this element and give its name and symbol.

Crystal Wang

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Problem 44

An element has two isotopes with masses of $62.9396 \mathrm{u}$ and $64.9278 \mathrm{u}$, and $30.83 \%$ of the atoms are the heavier isotope. Calculate the atomic mass of this element and give its name and symbol.

Crystal Wang

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Problem 45

Naturally occurring rubidium is $72.17 \%^{85} \mathrm{Rb}$ (atomic mass $=84.912 \mathrm{u}$ ). The remaining atoms are ${ }^{87} \mathrm{Rb}$ (atomic mass $=86.909 \mathrm{u}$ ). Calculate the atomic mass of $\mathrm{Rb}$.

Crystal Wang

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Problem 46

Naturally occurring indium is $95.7 \%{ }^{115} \mathrm{In}$ (atomic mass = $114.904 \mathrm{u}$ ). The remaining atoms are ${ }^{113}$ In (atomic mass = $112.904 \mathrm{u}) .$ Calculate the atomic mass of In.

Crystal Wang

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Problem 47

The mass spectrum of an element shows that $78.99 \%$ of the atoms have a mass of $23.985 \mathrm{u}, 10.00 \%$ have a mass of $24.986 \mathrm{u}$, and the remaining $11.01 \%$ have a mass of $25.982 \mathrm{u}$.
(a) Calculate the atomic mass of this element.
(b) Give the symbol for each of the isotopes present.

Crystal Wang

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Problem 48

The mass spectrum of an element shows that $92.2 \%$ of the atoms have a mass of $27.977 \mathrm{u}, 4.67 \%$ have a mass of $28.976 \mathrm{u}$, and the remaining $3.10 \%$ have a mass of $29.974 \mathrm{u}$.
(a) Calculate the atomic mass of this element.
(b) Give the symbol for each of the isotopes present.

Crystal Wang

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Problem 49

The most intense peak in a mass spectrum is assigned a height of 100 units. The following spectrum was obtained from a sample of an element. Use the data to calculate the atomic mass of the element. Identify the element.

Crystal Wang

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Problem 50

The most intense peak in a mass spectrum is assigned a eight of 100 units. The following spectrum was obtained rom a sample of an element. Use the data to calculate the tomic mass of the element. Identify the element.

Crystal Wang

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Problem 51

Antimony occurs naturally as two isotopes, one with a mass of $120.904 \mathrm{u}$ and the other with a mass of $122.904 \mathrm{u} .$
(a) Give the symbol that identifies each of these isotopes of antimony.
(b) Get the atomic mass of antimony from the periodic table and use it to calculate the natural abundance of each of these isotopes.

Crystal Wang

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Problem 52

Bromine occurs naturally as two isotopes, one with a mass of $78.918 \mathrm{u}$ and the other with a mass of $80.916 \mathrm{u}$.
(a) Give the symbol that identifies each of these isotopes of bromine.
(b) Get the atomic mass of bromine from the periodic table and use it to calculate the natural abundance of each of these isotopes.

Crystal Wang

Numerade Educator

Problem 53

Give a name and symbol for an element in the fifth period that is in the same group with
(a) sodium.
(b) Fe.
(c) bromine.
(d) $\mathrm{Ne}$.

Natalie Johns

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Problem 54

Give a name and symbol for an element in the sixth period that is in the same group with
(a) Ge.
(b) magnesium.
(c) Y.
(d) arsenic.

Natalie Johns

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Problem 55

Give a name and symbol for an element that is in the same group with
(a) $\mathrm{T}_{\mathrm{i}}$
(b) oxygen.
(c) fluorine.
(d) $\mathrm{Ba}$.

Natalie Johns

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Problem 56

Give a name and symbol for an element that is in the same group with
(a) argon.
(b) $\mathrm{N}$.
(c) Os.
(d) tungsten.

Natalie Johns

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Problem 57

Identify each of the following elements as a representative, a transition, or an inner transition element from its position in the periodic table.
(a) silicon
(b) $\mathrm{Cr}$
(c) magnesium
(d) $\mathrm{Np}$

Natalie Johns

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Problem 58

Identify each of the following elements as a representative, a transition, or an inner transition element from its position in the periodic table.
(a) barium
(b) $\mathrm{Mo}$
(c) $\vec{F}$
(d) hafnium

Natalie Johns

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Problem 59

Identify each of the following elements as a representative, a transition, or an inner transition element from its position in the periodic table.
(a) $\mathrm{Xe}$
(b) iron
(c) $\mathrm{K}$
(d) europium

Natalie Johns

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Problem 60

Identify each of the following elements as a representative, a transition, or an inner transition element from its position in the periodic table.
(a) $\mathrm{Br}$
(b) platinum
(c) rubidium
(d) $\mathrm{U}$

Natalie Johns

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Problem 61

Give the symbol and name for
(a) the alkali metal in the same period as chlorine.
(b) a halogen in the same period as magnesium.
(c) the heaviest alkaline earth metal.
(d) a noble gas in the same period as carbon.

Natalie Johns

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Problem 62

Give the symbol and name tor
(a) the alkaline earth element in the same period as sulfur.
(b) a noble gas in the same period as potassium.
(c) the heaviest alkali metal.
(d) a halogen in the same period as tin (Sn).

Natalie Johns

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Problem 63

How many elements are in each of the following?
(a) the alkali metals
(b) the halogens
(c) the lanthanides
(d) the sixth period
(e) Group $2 \mathrm{~B}$

Natalie Johns

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Problem 64

How many elements are there in Group $4 \mathrm{~A}$ of the periodic table? Give the name and symbol of each of these elements. Tell whether each is a metal, nonmetal, or metalloid.

Nicole Smina

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Problem 65

Which two elements would you expect to exhibit the greatest similarity in physical and chemical properties: Na. Kr. P. Ra, Sr. Te? Explain vour choice.

Natalie Johns

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Problem 66

Of the following elements, which two elements would you expect to exhibit the greatest similarity in physical and chemical properties: $\mathrm{Cl}, \mathrm{P}, \mathrm{S}, \mathrm{Se}, \mathrm{Ti}$ ? Explain your choice.

Jennifer Hudspeth

Jennifer Hudspeth

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Problem 67

Which two elements would you expect to exhibit the greatest similarity in physical and chemical properties:
B, C, Hf, Pb, Pr, Sn? Explain your choice.

Natalie Johns

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Problem 68

Which two elements would you expect to exhibit the greatest similarity in physical and chemical properties:
H, $\mathrm{Cl}$, I, Te, W, U? Explain your choice.

Natalie Johns

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Problem 69

Write the molecular formula of the molecules pictured below.

Crystal Wang

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Problem 70

Write the molecular formula of the molecules pictured below.

Crystal Wang

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Problem 71

Draw a ball-and-stick picture of $\mathrm{SF}_{2}$ (sulfur is located between the two fluorine atoms).

Natalie Johns

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Problem 72

Draw a ball-and-stick picture of $\mathrm{SO}_{2}$ (sulfur is located between the two oxygen atoms).

Natalie Johns

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Problem 73

Calculate the molecular mass of each of the following molecules.
(a) $\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}$
(b) $\mathrm{NOCl}_{2}$
(c) $\mathrm{N}_{2} \mathrm{O}_{3}$

Crystal Wang

Numerade Educator

Problem 74

Calculate the molecular mass of each of the following molecules.
(a) $\mathrm{P}_{4} \mathrm{O}_{10}$
(b) $\mathrm{C}_{6} \mathrm{H}_{7} \mathrm{~N}$
(c) $\mathrm{H}_{3} \mathrm{PO}_{4}$

Crystal Wang

Numerade Educator

Problem 75

Aspartame is an artificial sweetener that has the formula $\mathrm{C}_{14} \mathrm{H}_{18} \mathrm{~N}_{2} \mathrm{O}_{5} .$ What is the molecular mass of aspartame?

Crystal Wang

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Problem 76

The compound $\mathrm{B}_{10} \mathrm{H}_{14}$ has an unusual structure, with some of the hydrogen atoms bridging between two of the boron atoms. What is the molecular mass of $\mathrm{B}_{10} \mathrm{H}_{14} ?$

Crystal Wang

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Problem 77

Write the symbol for the monatomic ion that is expected for each of the following elements.
(a) iodine
(b) magnesium
(c) oxygen
(d) sodium

Natalie Johns

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Problem 78

Write the symbol for the monatomic ion that is expected for each of the following elements.
(a) potassium
(b) bromine
(c) barium
(d) sulfur

Natalie Johns

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Problem 79

What is the empirical formula for the compound made from each of the following pairs of ions?
(a) $\mathrm{Ca}^{2+}$ and $\mathrm{S}^{2-}$
(b) $\mathrm{Mg}^{2+}$ and $\mathrm{N}^{3-}$
(c) $\mathrm{Fe}^{2+}$ and $\mathrm{F}^{-}$

Natalie Johns

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Problem 80

What is the empirical formula for the compound made from each of the following pairs of ions?
(a) $\mathrm{Li}^{+}$ and $\mathrm{I}^{-}$
(b) $\mathrm{Cs}^{+}$ and $\mathrm{O}^{2-}$
(c) $\mathrm{Y}^{3+}$ and $\mathrm{Cl}^{-}$

Natalie Johns

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Problem 81

Write the empirical formula for the ionic compound made from each of the following pairs of elements.
(a) calcium and chlorine
(b) rubidium and sulfur
(c) lithium and nitrogen
(d) yttrium and selenium

Natalie Johns

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Problem 82

Write the empirical formula for the ionic compound made from each of the following pairs of elements.
(a) magnesium and fluorine
(b) sodium and oxygen
(c) scandium and selenium
(d) barium and nitrogen

Natalie Johns

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Problem 83

Write the formula and charge of
(a) the hydroxide ion.
(b) the chlorate ion.
(c) the permanganate ion.

Natalie Johns

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Problem 84

Write the formula and charge of
(a) the chromate ion.
(b) the carbonate ion.
(c) the sulfate ion.

Natalie Johns

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Problem 85

Write the formula and charge of
(a) the hydrogen sulfate ion.
(b) the cyanide ion.
(c) the dihydrogen phosphate ion.

Natalie Johns

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Problem 86

Write the formula and charge of
(a) the perchlorate ion.
(b) the sulfite ion.
(c) the hydrogen carbonate ion.

Natalie Johns

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Problem 87

Write the formula of
(a) magnesium nitrite.
(b) lithium phosphate.
(c) barium cyanide.
(d) ammonium sulfate.

Crystal Wang

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Problem 88

Write the formula of
(a) sodium nitrate.
(b) beryllium hydroxide.
(c) ammonium acetate.
(d) potassium sulfite.

Crystal Wang

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Problem 89

Write the formula of
(a) strontium nitrate.
(b) sodium dihydrogen phosphate.
(c) potassium perchlorate.
(d) lithium hydrogen sulfate.

Crystal Wang

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Problem 90

Give the symbol, including the correct charge, for each of the following ions.
(a) barium ion
(b) perchlorate ion
(c) $\operatorname{cobalt}(\mathrm{II})$ ion
(d) sulfate ion

Crystal Wang

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Problem 91

Calculate the formula mass for each of the following compounds.
(a) $\mathrm{K}_{2} \mathrm{SO}_{4}$
(b) $\mathrm{AgNO}_{3}$
(c) $\mathrm{NH}_{4} \mathrm{Cl}$

Crystal Wang

Numerade Educator

Problem 92

Calculate the formula mass for each of the following compounds.
(a) $\mathrm{Na} \mathrm{OH}$
(b) $\mathrm{K}_{2} \mathrm{CO}_{3}$
(c) $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$

Crystal Wang

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Problem 93

Write the name of each of the following ionic compounds.
(a) Lil
(b) $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
(c) $\mathrm{Na}_{3} \mathrm{PO}_{4}$
(d) $\mathrm{Ba}\left(\mathrm{ClO}_{4}\right)_{2}$

Crystal Wang

Numerade Educator

Problem 94

Write the name of each of the following ionic compounds.
(a) $\mathrm{NH}_{4} \mathrm{Br}$
(b) $\mathrm{BaCl}_{2}$
(c) $\mathrm{K}_{2} \mathrm{O}$
(d) $\mathrm{Sr}\left(\mathrm{NO}_{3}\right)_{2}$

Crystal Wang

Numerade Educator

Problem 95

Write the modern name of each of the following transition-metal compounds.
(a) $\mathrm{CoCl}_{3}$
(b) $\mathrm{FeSO}_{4}$
(c) $\mathrm{CuO}$

Crystal Wang

Numerade Educator

Problem 96

Write the modern name of each of the following transition-metal compounds.
(a) $\mathrm{RhBr}_{2}$
(b) $\mathrm{CuCN}$
(c) $\mathrm{V}\left(\mathrm{NO}_{3}\right)_{3}$

Crystal Wang

Numerade Educator

Problem 97

Write the formula of
(a) manganese(III) sulfide.
(b) iron(II) cyanide.
(c) potassium sulfide.
(d) mercury(II) chloride.

Crystal Wang

Numerade Educator

Problem 98

Write the formula of
(a) calcium nitride.
(b) chromium(III) perchlorate.
(c) tin(II) fluoride.
(d) potassium permanganate.

Crystal Wang

Numerade Educator

Problem 99

Write the formula and name of the acid related to the following ions.
(a) chloride
(b) nitrite
(c) perchlorate

Crystal Wang

Numerade Educator

Problem 100

Write the formula and name of the acid related to the following ions.
(a) cyanide
(b) nitrate
(c) phosphate

Crystal Wang

Numerade Educator

Problem 101

What is the name of each of the following acids?
(a) $\mathrm{H}_{3} \mathrm{PO}_{4}$
(b) $\mathrm{H}_{2} \mathrm{SO}_{3}$
(c) $\mathrm{H}_{2} \mathrm{Te}$

Crystal Wang

Numerade Educator

Problem 102

What is the name of each of the following acids?
(a) $\mathrm{H}_{2} \mathrm{CO}_{3}$
(b) $\mathrm{HBr}$
(c) $\mathrm{HNO}_{2}$

Crystal Wang

Numerade Educator

Problem 103

Some people who have hypertension or heart problems use potassium chloride as a substitute for sodium chloride. What is the formula of potassium chloride?

Crystal Wang

Numerade Educator

Problem 104

The compound $\mathrm{MnO}$ is added to glass during manufacture to improve its clarity. Write the name of $\mathrm{MnO}$.

Crystal Wang

Numerade Educator

Problem 105

Write the formula for each of the following molecular compounds.
(a) sulfur tetrafluoride
(b) nitrogen trichloride
(c) dinitrogen pentoxide
(d) chlorine trifluoride

Crystal Wang

Numerade Educator

Problem 106

Write the formula for each of the following molecular compounds.
(a) sulfur difluoride
(b) silicon tetrachloride
(c) gallium trichloride
(d) dinitrogen trioxide

Crystal Wang

Numerade Educator

Problem 107

Write the name of each of the following molecular compounds.
(a) $\mathrm{PBr}_{5}$
(b) $\mathrm{SeO}_{2}$
(c) $\mathrm{B}_{2} \mathrm{Cl}_{4}$
(d) $\mathrm{S}_{2} \mathrm{Cl}_{2}$

Crystal Wang

Numerade Educator

Problem 108

Write the name of each of the following molecular compounds.
(a) HI
(b) $\mathrm{NF}_{3}$
(c) $\mathrm{SO}_{2}$
(d) $\mathrm{N}_{2} \mathrm{Cl}_{4}$

Crystal Wang

Numerade Educator

Problem 109

Write the name of the organic compounds pictured below.
(a)
<smiles>CCCCCCCCC</smiles>
(b)
<smiles>CCCC(C)CCC</smiles>

Crystal Wang

Numerade Educator

Problem 110

Write the name of the organic compounds pictured below.

Crystal Wang

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Problem 111

Write the name of the organic compounds pictured below.

Crystal Wang

Numerade Educator

Problem 112

Write the name of the organic compounds pictured below.

Crystal Wang

Numerade Educator

Problem 113

Of the two compounds, $\mathrm{LiCl}$ and $\mathrm{CO}_{2}$, which one do you predict will dissolve in water and which one will be a gas? Explain your answer.

Crystal Wang

Numerade Educator

Problem 114

Of the two compounds, $\mathrm{Na}_{2} \mathrm{CO}_{3}$ and $\mathrm{Cl}_{2}$, which one do you predict will dissolve in water and which one will be a gas? Explain your answer.

Crystal Wang

Numerade Educator

Problem 115

Which beaker below best pictures sodium sulfite in water solution? Explain your answer.

Crystal Wang

Numerade Educator

Problem 116

Which beaker in problem 2.115 best pictures lithium sulfide in water solution? Explain your answer.

Crystal Wang

Numerade Educator

Problem 117

Which of the following substances conducts an electrical current when dissolved in water? Identify the formulas and charges of the ions present in the conducting solutions.
(a) $\mathrm{FeCl}_{3}$
(b) $\mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}$ (urea)
(c) $\mathrm{NH}_{4} \mathrm{Br}$
(d) $\mathrm{NaClO}_{4}$
(e) $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$

Crystal Wang

Numerade Educator

Problem 118

Which of the following substances conducts an electrical current when dissolved in water? Identify the formulas and charges of the ions present in the conducting solutions.
(a) $\mathrm{AlBr}_{3}$
(b) $\mathrm{C}_{2} \mathrm{H}_{4}(\mathrm{OH})_{2}$ (ethylene glycol)
(c) $\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}$
(d) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$
(e) $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$

Crystal Wang

Numerade Educator

Problem 119

Predict the formula of an ionic compound formed from calcium and nitrogen.

Crystal Wang

Numerade Educator

Problem 120

Write the formula of iron(III) sulfate.

Crystal Wang

Numerade Educator

Problem 121

The common name for a slurry of $\mathrm{Mg}(\mathrm{OH})_{2}$ in water is Milk of Magnesia. Give the proper name of this compound.

Crystal Wang

Numerade Educator

Problem 122

Write the formula of potassium nitrate and ammonium carbonate.

Crystal Wang

Numerade Educator

Problem 123

Write the symbol, including atomic number, mass number, and charge, for each of the following species.
(a) a halogen with a mass number of 35 and a $1-$ charge
(b) an alkali metal with 18 electrons, 20 neutrons, and a 1+ charge

Crystal Wang

Numerade Educator

Problem 124

Write the symbol, including atomic number, mass number, and charge, for each of the following species.
(a) a neutral noble-gas element with 21 neutrons in its nucleus
(b) an alkaline earth metal with a mass number of 40 and a $2+$ charge

Crystal Wang

Numerade Educator

Problem 125

Name each of the following compounds, and indicate whether each is ionic or molecular.
(a) $\mathrm{NO}$
(b) $\mathrm{Y}_{2}\left(\mathrm{SO}_{4}\right)_{3}$
(c) $\mathrm{Na}_{2} \mathrm{O}$
(d) $\mathrm{NBr}_{3}$

Crystal Wang

Numerade Educator

Problem 126

Write the formula of each of the following compounds, and indicate whether each is ionic or molecular.
(a) calcium phosphate
(b) germanium dioxide
(c) iron(III) sulfate
(d) phosphorus tribromide

Crystal Wang

Numerade Educator

Problem 127

Partial information is given in each column in the following table. Fill in the blank spaces. $\begin{array}{lcccc}\text { Symbol } & - & - & - & { }^{28} \mathrm{Si}^{2-} \\ \text { Atomic number } & - & - & 49 & - \\ \text { Mass number } & 70 & 103 & - & - \\ \text { Charge } & - & 3+ & 1+ & - \\ \text { Number of } & 31 & - & - & - \\ \text { protons } & & & & \\ \text { Number of } & 28 & 42 & - & - \\ \text { electrons } & & & & \\ \text { Number of } & - & - & 65 & -\end{array}$ 3 1

Crystal Wang

Numerade Educator

Problem 128

Plutonium was first isolated by Glenn Seaborg and coworkers in the early 1940 s as the ${ }^{239} \mathrm{Pu}$ isotope; they made it by a nuclear reaction of deuterium with uranium. Give the numbers of protons, neutrons, and electrons in an atom of this isotope of plutonium.

Crystal Wang

Numerade Educator

Problem 129

From the list of elements $\mathrm{Li}, \mathrm{Ca}, \mathrm{Fe}, \mathrm{Al}, \mathrm{C} 1, \mathrm{O}, \mathrm{C},$ and
$\mathrm{N},$ write the formula and name of a compound that fits each of the following descriptions.
(a) an ionic compound with the formula $\mathrm{MX}_{2},$ where $\mathrm{M}$ is an alkaline earth metal and $X$ is a nonmetal
(b) a molecular substance with the formula $\mathrm{AB}_{2}$, where $A$ is a Group $4 A$ element and $B$ is a Group $6 A$ element
(c) a compound with the formula $\mathrm{M}_{2} \mathrm{X}_{3},$ where $\mathrm{M}$ is a transition metal and $X$ is a nonmetal

Crystal Wang

Numerade Educator

Problem 130

Describe the compositions of the three isotopes of hydrogen. Write the symbol and give the name of each isotope.

Crystal Wang

Numerade Educator

Problem 131

Write the symbol for each of the following species.
(a) a cation with a mass number of $23,$ an atomic num ber of 11 , and a charge of $1+$
(b) a member of the nitrogen group (Group 5 A) that has a $3+$ charge, 48 electrons, and 70 neutrons
(c) a noble gas with no charge and 48 neutrons

Crystal Wang

Numerade Educator

Problem 132

Write the formula for each of the following compounds.
(a) sodium selenide
(b) nickel(II) bromide
(c) dinitrogen pentoxide
(d) copper(II) sulfate
(e) ammonium sulfite

Crystal Wang

Numerade Educator

Problem 133

The relative abundance of ${ }^{6} \mathrm{Li}$ is known to only three significant figures $(7.42 \%) .$ How can the atomic mass of lithium have four significant figures?

Crystal Wang

Numerade Educator

Problem 134

An atom contains 38 protons and 40 neutrons.
(a) Write the symbol for this atom.
(b) In which group of the periodic table is this element located?
(c) What is the charge of the monatomic ion this element forms?
(d) What is the symbol of an atom in the same group that contains 12 neutrons?

Crystal Wang

Numerade Educator

Problem 135

The accepted atomic mass of nitrogen is $14.0067 \mathrm{u}$. Approximately $99.632 \%$ of natural nitrogen is ${ }^{14} \mathrm{~N}$, which has an isotopic mass of $14.0031 \mathrm{u}$. The remaining nitrogen is ${ }^{15} \mathrm{~N}$. What is the isotopic mass of ${ }^{15} \mathrm{~N}$ in atomic mass units?

Crystal Wang

Numerade Educator

Problem 136

There are two stable isotopes of carbon. If natural carbon consists of $98.938 \%{ }^{12} \mathrm{C}$ and the accepted atomic mass of carbon is $12.0107 \mathrm{u}$, what is the isotopic mass of a ${ }^{13} \mathrm{C}$ atom? Diamond is made of pure carbon and has excellent mechanical, electrical, and light transmission properties. Recently, scientists made some diamonds out of ${ }^{13} \mathrm{C}$ and found that they had even better physical properties than "normal" diamonds do.

Crystal Wang

Numerade Educator