Introductory Chemistry

Problem 8

What does the atomic number of an element specify?

David Collins

Numerade Educator

Problem 9

What is a chemical symbol?

David Collins

Numerade Educator

Problem 10

List some examples of how elements were named.

David Collins

Numerade Educator

00:43

Problem 11

What was Dmitri Mendeleev's main contribution to our modern understanding of chemistry?

David Collins

Numerade Educator

Problem 12

What is the main idea in the periodic law?

David Collins

Numerade Educator

01:18

Problem 13

How is the periodic table organized?

David Collins

Numerade Educator

00:36

Problem 14

What are the properties of metals? Where are metals found on the periodic table?

David Collins

Numerade Educator

00:56

Problem 15

What are the properties of nonmetals? Where are nonmetals found on the periodic table?

David Collins

Numerade Educator

Problem 16

Where on the periodic table are metalloids found?

David Collins

Numerade Educator

Problem 17

What is a family or group of elements?

David Collins

Numerade Educator

Problem 18

Locate each group of elements on the periodic table and list its group number.
(a) alkali metals
(b) alkaline earth metals
(c) halogens
(d) noble gases

David Collins

Numerade Educator

Problem 19

What is an ion?

David Collins

Numerade Educator

00:31

Problem 20

What is an anion? What is a cation?

David Collins

Numerade Educator

01:05

Locate each group on the periodic table and list the charge of the ions it tends to form.
(a) Group $1 \mathrm{A}$
(b) Group $2 \mathrm{A}$
(c) Group $3 \mathrm{A}$
(d) Group $6 \mathrm{A}$
(e) Group $7 \mathrm{A}$

David Collins

Numerade Educator

Problem 22

What are isotopes?

David Collins

Numerade Educator

01:32

Problem 23

What is the percent natural abundance of isotopes?

Eugene Schneider

University of Minnesota - Twin Cities

00:13

Problem 24

What is the mass number of an isotope?

David Collins

Numerade Educator

00:54

Problem 25

What notations are commonly used to specify isotopes? What do each of the numbers in these symbols mean?

David Collins

Numerade Educator

00:28

Problem 26

What is the atomic mass of an element?

David Collins

Numerade Educator

01:04

Problem 27

Which statements are inconsistent with Dalton's atomic theory as it was originally stated? Explain your answers.
(a) All carbon atoms are identical.
(b) Helium atoms can be split into two hydrogen atoms.
(c) An oxygen atom combines with 1.5 hydrogen atoms to form water molecules.
(d) Two oxygen atoms combine with a carbon atom to form carbon dioxide molecules.

David Collins

Numerade Educator

01:07

Problem 28

Which statements are consistent with Dalton's atomic theory as it was originally stated? Explain your answers.
(a) Calcium and titanium atoms have the same mass.
(b) Neon and argon atoms are the same.
(c) All cobalt atoms are identical.
(d) Sodium and chlorine atoms combine in a 1: 1 ratio to form sodium chloride.

David Collins

Numerade Educator

01:06

Problem 29

Which statements are inconsistent with Rutherford's nuclear theory as it was originally stated? Explain your answers.
(a) Helium atoms have two protons in the nucleus and two electrons outside the nucleus.
(b) Most of the volume of hydrogen atoms is due to the nucleus.
(c) Aluminum atoms have 13 protons in the nucleus and 22 electrons outside the nucleus.
(d) The majority of the mass of nitrogen atoms is due to their 7 electrons.

David Collins

Numerade Educator

01:11

Problem 30

Which statements are consistent with Rutherford's nuclear theory as it was originally stated? Explain your answers.(a) Atomic nuclei are small compared to the size of atoms.
(b) The volume of an atom is mostly empty space.
(c) Neutral potassium atoms contain more protons than electrons.
(d) Neutral potassium atoms contain more neutrons than protons.

David Collins

Numerade Educator

00:48

Problem 31

If atoms are mostly empty space and atoms compose all ordinary matter, why does solid matter seem to have no space within it?

David Collins

Numerade Educator

00:36

Problem 32

Rutherford's experiment indicated that matter was not as uniform as it appears. What part of his experimental results implied this idea? Explain.

David Collins

Numerade Educator

00:51

Problem 33

Which statements about electrons are true?
(a) Electrons repel each other.
(b) Electrons are attracted to protons.
(c) Some electrons have a charge of $1-$ and some have no charge.
(d) Electrons are much lighter than neutrons.

David Collins

Numerade Educator

01:04

Problem 34

Which statements about electrons are false?
(a) Most atoms have more electrons than protons.
(b) Electrons have a charge of $1-$.
(c) If an atom has an equal number of protons and electrons, it will be charge-neutral.
(d) Electrons experience an attraction to protons.

David Collins

Numerade Educator

00:59

Problem 35

Which statements about protons are true?
(a) Protons have twice the mass of neutrons.
(b) Protons have the same magnitude of charge as electrons but are opposite in sign.
(c) Most atoms have more protons than electrons.
(d) Protons have a charge of $1+$

David Collins

Numerade Educator

01:05

Problem 36

Which statements about protons are false?
(a) Protons have about the same mass as neutrons.
(b) Protons have about the same mass as electrons.
(c) Some atoms don't have any protons.
(d) Protons have the same magnitude of charge as neutrons but are opposite in sign.

David Collins

Numerade Educator

00:27

Problem 37

How many electrons would it take to equal the mass of a proton?

David Collins

Numerade Educator

Problem 38

A helium nucleus has two protons and two neutrons. How many electrons would it take to equal the mass of a helium nucleus?

David Collins

Numerade Educator

00:38

Problem 39

What mass of electrons is required to neutralize the charge of $1.0 \mathrm{g}$ of protons?

David Collins

Numerade Educator

01:00

Problem 40

What mass of protons is required to neutralize the charge of $1.0 \mathrm{g}$ of electrons?

David Collins

Numerade Educator

00:29

Problem 41

Find the atomic number (Z) for each element.
(a) Fr
(b) Kr
(c) Pa
(d) Ge
(e) Al

David Collins

Numerade Educator

00:29

Problem 42

Find the atomic number (Z) for each element.
(a) $\mathrm{Si}$
(b) $\mathrm{W}$
(c) $\mathrm{Ni}$
(d) $\mathrm{Rn}$
(e) $\mathrm{Sr}$

David Collins

Numerade Educator

00:43

Problem 43

How many protons are in the nucleus of an atom of each element?
(a) Ar
(b) Sn
(c) Xe
(d) O
(e) TI

David Collins

Numerade Educator

00:34

Problem 44

How many protons are in the nucleus of an atom of each element?
(a) $\mathrm{Ti}$
(b)$\mathrm{Li}$
(c) $\mathrm{U}$
(d) $\mathrm{Br}$
(e) $\mathrm{F}$

David Collins

Numerade Educator

00:27

Problem 45

List the symbol and atomic number of each element.
(a) carbon
(b) nitrogen
(c) sodium
(d) potassium
(e) copper

David Collins

Numerade Educator

01:14

Problem 46

List the symbol and atomic number of each element.
(a) boron
(b) neon
(c) silver
(d) mercury
(e) curium

Oluwapelumi Kolawole

Numerade Educator

00:26

Problem 47

List the name and the atomic number of each element.
(a) $\mathrm{Mn}$
(b) $\mathrm{Ag}$
(c) $\mathrm{Au}$
(d) $\mathrm{Pb}$
(e) $\mathrm{S}$

David Collins

Numerade Educator

00:28

Problem 48

List the name and the atomic number of each element.
(a) $\mathrm{Y}$
(b) $\mathrm{N}$
(c) $\mathrm{Ne}$
(d) $\mathrm{K}$
(e) $\mathrm{Mo}$

David Collins

Numerade Educator

Problem 49

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

Problem 50

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

00:44

Problem 51

Classify each element as a metal, nonmetal, or metalloid.
(a) $\mathrm{Sr}$
(b) $\mathrm{Mg}$
(c) $\mathrm{F}$
(d) $\mathrm{N}$
(e) $\mathrm{As}$

David Collins

Numerade Educator

00:47

Problem 52

Classify each element as a metal, nonmetal, or metalloid.
(a) $\mathrm{Na}$
(b) $\mathrm{Ge}$
(c) $\mathrm{Si}$
(d) $\mathrm{Br}$
(e) $\mathrm{Ag}$

David Collins

Numerade Educator

00:27

Problem 53

Which elements would you expect to lose electrons in chemical changes?
(a) potassium
(b) sulfur
(c) fluorine
(d) barium
(e) copper

David Collins

Numerade Educator

00:24

Problem 54

Which elements would you expect to gain electrons in chemical changes?
(a) nitrogen
(b) iodine
(c) tungsten
(d) strontium
(e) gold

David Collins

Numerade Educator

00:26

Problem 55

Which elements are main-group elements?
(a) $\mathrm{Te}$
(b) $\mathrm{K}$
(c) $\mathrm{V}$
(d) $\mathrm{Re}$
(e) $\mathrm{Ag}$

David Collins

Numerade Educator

00:28

Problem 56

Which elements are not main-group elements?
(a) $\mathrm{AI}$
(b) $\mathrm{Br}$
(c) $\mathrm{Mo}$
(d) $\mathrm{Cs}$
(e) $\mathrm{Pb}$

David Collins

Numerade Educator

00:24

Problem 57

Which elements are alkaline earth metals?
(a) sodium
(b) aluminum
(c) calcium
(d) barium
(e) lithium

David Collins

Numerade Educator

00:26

Problem 58

Which elements are alkaline earth metals?
(a) rubidium
(b) tungsten
(c) magnesium
(d) cesium
(e) beryllium

David Collins

Numerade Educator

Problem 59

Which elements are alkali metals?
(a) barium
(b) sodium
(c) gold
(d) tin
(e) rubidium

David Collins

Numerade Educator

00:19

Problem 60

Which elements are alkali metals?
(a) scandium
(b) iron
(c) potassium
(d) lithium
(e) cobalt

David Collins

Numerade Educator

Problem 61

Classify each element as a halogen, a noble gas, or neither.
(a) $\mathrm{CI}$
(b) $\mathrm{Kr}$
(c) $\mathrm{F}$
(d) $\mathrm{Ga}$
(e) $\mathrm{He}$

David Collins

Numerade Educator

00:39

Problem 62

Classify each element as a halogen, a noble gas, or neither.
(a) $\mathrm{Ne}$
(b) $\mathrm{Br}$
(c) $\mathrm{S}$
(d) $\mathrm{Xe}$
(e) $\mathrm{I}$

David Collins

Numerade Educator

Problem 63

To what group number does each element belong?
(a) oxygen
(b) aluminum
(c) silicon
(d) tin
(e) phosphorus

David Collins

Numerade Educator

00:19

Problem 64

To what group number does each element belong?
(a) germanium
(b) nitrogen
(c) sulfur
(d) carbon
(e) boron

David Collins

Numerade Educator

00:17

Problem 65

Which element do you expect to be most like sulfur? Why?
(a) nitrogen
(b) oxygen
(c) fluorine
(d) lithium
(e) potassium

David Collins

Numerade Educator

Problem 66

Which element do you expect to be most like magnesium? Why?
(a) potassium
(b) silver
(c) bromine
(d) calcium
(e) lead

David Collins

Numerade Educator

00:16

Problem 67

Which pair of elements do you expect to be most similar? Why?
(a) $\mathrm{Si}$ and $\mathrm{Si}$
(b) $\mathrm{CI}$ and $\mathrm{F}$
(c) g$\mathrm{Na}$ and $\mathrm{Mg}$
(d) $\mathrm{Mo}$ and $\mathrm{Sn}$
(e) $\mathrm{N}$ and $\mathrm{Ni}$

David Collins

Numerade Educator

00:16

Problem 68

Which pair of elements do you expect to be most similar? Why?
(a) $\mathrm{Ti}$ and $\mathrm{Ga}$
(b) $\mathrm{N}$ and $\mathrm{O}$
(c) g$\mathrm{Li}$ and $\mathrm{Na}$
(d) $\mathrm{Ar}$ and $\mathrm{Br}$
(e) $\mathrm{Ge}$ and $\mathrm{Ga}$

David Collins

Numerade Educator

00:18

Problem 69

Which element is a main-group nonmetal?
(a) $\mathrm{K}$
(b) $\mathrm{Fe}$
(c) $\mathrm{Sn}$
(d) $\mathrm{S}$

David Collins

Numerade Educator

00:34

Problem 70

Which element is a row 5 transition element?
Which element is a main-group nonmetal?
(a) $\mathrm{Sr}$
(b) $\mathrm{Pd}$
(c) $\mathrm{P}$
(d) $\mathrm{v}$

David Collins

Numerade Educator

Problem 71

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

Problem 72

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

00:47

Problem 73

Complete each ionization equation.
(a) $\mathrm{Na} \longrightarrow \mathrm{Na}^{+}+$ _____
(b) $\mathrm{O}+2 \mathrm{e}^{-} \longrightarrow$ _______
(c) $\mathrm{Ca} \longrightarrow \mathrm{Ca}^{2+}+$ _______
(d) $\mathrm{Cl}+\mathrm{e}^{-} \longrightarrow$ ________

David Collins

Numerade Educator

00:54

Problem 74

Complete each ionization equation.
(a) $\mathrm{Mg} \longrightarrow$ _______ $+2 e^{-}$.
(b) $\mathrm{Ba} \longrightarrow \mathrm{Ba}^{2+}+$ _____
(c) $\mathrm{I}+\mathrm{e}^{-} \longrightarrow$____
(d) Al $\longrightarrow$ ____ $+3 e^{-}$

David Collins

Numerade Educator

01:03

Problem 75

Determine the charge of each ion.
(a) oxygen ion with 10 electrons
(b) aluminum ion with 10 electrons
(c) titanium ion with 18 electrons
(d) iodine ion with 54 electrons

David Collins

Numerade Educator

01:06

Problem 76

Determine the charge of each ion.
(a) tungsten ion with 68 electrons
(b) tellurium ion with 54 electrons
(c) nitrogen ion with 10 electrons
(d) barium ion with 54 electrons

David Collins

Numerade Educator

01:13

Problem 77

Determine the number of protons and electrons in each ion.
(a) $\mathrm{Na}^{+}$
(b) $\mathrm{Ba}^{2+}$
(c) $\mathrm{O}^{2-}$
(d) $\mathrm{Co}^{3+}$

David Collins

Numerade Educator

01:01

Problem 78

Determine the number of protons and electrons in each ion.
(a) $\mathrm{Al}^{3+}$
(b) $\mathrm{S}^{2-}$
(c) $\mathrm{I}^{-}$
(d) $\mathrm{Ag}^{+}$

David Collins

Numerade Educator

01:19

Problem 79

Determine whether each statement is true or false. If false, correct it.
(a) The $\mathrm{Ti}^{2+}$ ion contains 22 protons and 24 electrons.
(b) The I $^{-}$ ion contains 53 protons and 54 electrons.
(c) The $\mathrm{Mg}^{2+}$ ion contains 14 protons and 12 electrons.
(d) The $\mathrm{O}^{2-}$ ion contains 8 protons and 10 electrons.

David Collins

Numerade Educator

01:15

Problem 80

Determine whether each statement is true or false. If false, correct it.
(a) The $\mathrm{Fe}^{2+}$ ion contains 29 protons and 26 electrons.
(b) The $\mathrm{Cs}^{+}$ ion contains 55 protons and 56 electrons.
(c) The $S e^{2-}$ ion contains 32 protons and 34 electrons.
(d) The $L i^{+}$ ion contains 3 protons and 2 electrons.

David Collins

Numerade Educator

00:50

Problem 81

Complete each ionization equation.
Predict the ion formed by each element.
(a) $\mathrm{Rb}$
(b) $\mathrm{K}$
(c) $\mathrm{AI}$
(d) $\mathrm{O}$

David Collins

Numerade Educator

00:37

Problem 82

Predict the ion formed by each element.
(a) $\mathrm{F}$
(b) $\mathrm{N}$
(c) $\mathrm{Mg}$
(d) $\mathrm{ Na}$

David Collins

Numerade Educator

00:56

Problem 83

Predict how many electrons each element will most likely gain or lose.
(a) $\mathrm{Ga}$
(b) $\mathrm{Li}$
(c) $\mathrm{Br}$
(d) $\mathrm{ S}$

David Collins

Numerade Educator

00:59

Problem 84

Predict how many electrons each element will most likely gain or lose.
(a) $\mathrm{I}$
(b) $\mathrm{Ba}$
(c) $\mathrm{Cs}$
(d) $\mathrm{Se}$

David Collins

Numerade Educator

Problem 85

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

Problem 86

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

01:04

Problem 87

Determine the atomic number and mass number for each isotope.
(a) the hydrogen isotope with 2 neutrons
(b) the chromium isotope with 28 neutrons
(c) the calcium isotope with 22 neutrons
(d) the tantalum isotope with 109 neutrons

David Collins

Numerade Educator

00:37

Problem 88

How many neutrons are in an atom with each atomic number and mass number?
(a) $\mathrm{Z}=28, \mathrm{A}=59$
(b) $\mathrm{Z}=92, \mathrm{A}=235$
(c) $\mathrm{Z}=21, \mathrm{A}=46$
(d) $\mathrm{Z}=18, \mathrm{A}=42$

David Collins

Numerade Educator

01:09

Problem 89

Write isotopic symbols in the form $\underset{Z}{\mathrm{A}} \mathrm{X}$ for each isotope.
(a) the oxygen isotope with 8 neutrons
(b) the fluorine isotope with 10 neutrons
(c) the sodium isotope with 12 neutrons
(d) the aluminum isotope with 14 neutrons

David Collins

Numerade Educator

01:05

Problem 90

Write isotopic symbols in the form $X$ -A (for example, $C-13$ ) for each isotope.
(a) the iodine isotope with 74 neutrons
(b) the phosphorus isotope with 16 neutrons
(c) the uranium isotope with 234 neutrons
(d) the argon isotope with 22 neutrons

David Collins

Numerade Educator

01:03

Problem 91

Write the symbol for each isotope in the form $\underset{2}{2} X$
(a) cobalt-60
(b) neon-22
(c) iodine-131
(d) plutonium-244

David Collins

Numerade Educator

00:54

Problem 92

Write the symbol for each isotope in the form $\underset{\mathrm{Z}}{\mathrm{X}}$.
(a) $\mathrm{U}-235$
(b) $\mathrm{V}-52$
(c) $\mathrm{P}-32$
(d) Xe-144

David Collins

Numerade Educator

00:47

Problem 93

Determine the number of protons and neutrons in each isotope.
(a) $\quad \frac{23}{11} \mathrm{Na}$
(b) $\quad \frac{266}{88} \mathrm{Ra}$
(c) $\quad \frac{208}{82} \mathrm{Pb}$
(d) $\quad \frac{14}{7} \mathrm{N}$

David Collins

Numerade Educator

00:44

Problem 94

Determine the number of protons and neutrons in each isotope.
(a) $\frac{33}{15} \mathrm{P}$
(b) $\frac{40}{19} \mathrm{K}$
(c) $\frac{222}{86} \mathrm{Rn}$
(d) $\frac{99}{43} \mathrm{Tc}$

David Collins

Numerade Educator

Problem 95

Carbon-14, present within living organisms and substances derived from living organisms, is often used to establish the age of fossils and artifacts. Determine the number of protons and neutrons in a carbon-14 isotope and write its symbol in the form $\underset{Z}{~} \mathrm{X}$.

David Collins

Numerade Educator

00:30

Problem 96

Plutonium-239 is used in nuclear bombs. Determine the number of protons and neutrons in plutonium-239 and write its symbol in the form $\underset{\mathbf{Z}}{\mathbf{A}} \mathbf{X}$.

David Collins

Numerade Educator

00:32

Problem 97

Rubidium has two naturally occurring isotopes: Rb-85 with mass 84.9118 amu and a natural abundance of $72.17 \%,$ and Rb-87 with mass 86.9092 amu and a natural abundance of 27.83\%. Calculate the atomic mass of rubidium.

David Collins

Numerade Educator

00:50

Problem 98

Silicon has three naturally occurring isotopes: Si-28 with mass 27.9769 amu and a natural abundance of $92.21 \%, \mathrm{Si}-29$ with mass 28.9765 amu and a natural abundance of $4.69 \%$ and Si-30 with mass 29.9737 amu and a natural abundance of $3.10 \% .$ Calculate the atomic mass of silicon.

David Collins

Numerade Educator

01:14

Problem 99

Bromine has two naturally occurring isotopes (Br-79 and Br- 81 ) and an atomic mass of 79.904 amu.
(a) If the natural abundance of $\mathrm{Br}-79$ is $50.69 \%,$ what is the natural abundance of Br- $81 ?$
(b) If the mass of $\mathrm{Br}-81$ is 80.9163 amu, what is the mass of Br-79?

David Collins

Numerade Educator

View

Problem 100

Silver has two naturally occurring isotopes (Ag-107 and Ag-109).
(a) Use the periodic table to find the atomic mass of silver.
(b) If the natural abundance of $\mathrm{Ag}-107$ is $51.84 \%,$ what is the natural abundance of Ag-109?
(c) If the mass of $\mathrm{Ag}-107$ is 106.905 amu, what is the mass of Ag-109?

Jean Gephart

Numerade Educator

Problem 101

An element has two naturally occurring isotopes. Isotope 1 has a mass of 120.9038 amu and a relative abundance of $57.4 \%,$ and isotope 2 has a mass of 122.9042 amu and a relative abundance of $42.6 \% .$ Find the atomic mass of this element and, referring to the periodic table, identify it.

David Collins

Numerade Educator

01:12

Problem 102

Copper has two naturally occurring isotopes. Cu-63 has a mass of 62.939 amu and relative abundance of $69.17 \%$ Use the atomic weight of copper to determine the mass of the other copper isotope.

David Collins

Numerade Educator

00:24

Problem 103

Electrical charge is sometimes reported in coulombs (C). On this scale, 1 electron has a charge of $-1.6 \times 10^{-19} \mathrm{C}$ Suppose your body acquires $-125 \mathrm{mC}$ (millicoulombs) of charge on a dry day. How many excess electrons has it acquired? (Hint: Use the charge of an electron in coulombs as a conversion factor between charge and electrons.)

David Collins

Numerade Educator

00:23

Problem 104

How many excess protons are in a positively charged object with a charge of $+398 \mathrm{mC}$ (millicoulombs)? The charge of 1 proton is $+1.6 \times 10^{-19} \mathrm{C}$. (Hint: See previous problem.)

David Collins

Numerade Educator

01:09

Problem 105

The hydrogen atom contains 1 proton and 1 electron. The radius of the proton is approximately $1.0 \mathrm{fm}$ (femtometer), and the radius of the hydrogen atom is approximately $53 \mathrm{pm}$ (picometers). Calculate the volume of the nucleus and the volume of the atom for hydrogen. What percentage of the hydrogen atom's volume does the nucleus occupy?

David Collins

Numerade Educator

01:00

Problem 106

Carbon-12 contains 6 protons and 6 neutrons. The radius of the nucleus is approximately $2.7 \mathrm{fm},$ and the radius of the atom is approximately $70 \mathrm{pm} .$ Calculate the volume of the nucleus and the volume of the atom. What percentage of the carbon atom's volume does the nucleus occupy?

David Collins

Numerade Educator

03:17

Problem 107

Prepare a table like Table 4.2 for the four different isotopes of Sr that have the natural abundances and masses listed here.Use your table and the listed atomic masses to calculate the atomic mass of strontium.

David Collins

Numerade Educator

01:08

Problem 108

Determine the number of protons and neutrons in each isotope of chromium and use the listed natural abundances and masses to calculate its atomic mass.

David Collins

Numerade Educator

Problem 109

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

Problem 110

Fill in the blanks to complete the table.

Eugene Schneider

University of Minnesota - Twin Cities

01:40

Problem 111

Europium has two naturally occurring isotopes: Eu-151 with a mass of 150.9198 amu and a natural abundance of $47.8 \%,$ and Eu-153. Use the atomic mass of europium to find the mass and natural abundance of Eu-153.

David Collins

Numerade Educator

View

Problem 112

Rhenium has two naturally occurring isotopes: Re-185 with a natural abundance of $37.40 \%$ and Re-187 with a natural abundance of $62.60 \% .$ The sum of the masses of the two isotopes is 371.9087 amu. Find the masses of the individual isotopes.

Jean Gephart

Numerade Educator

00:34

Problem 113

Chapter 1 describes the difference between observations, laws, and theories. Cite two examples of theories from this chapter and explain why they are theories.

David Collins

Numerade Educator

00:30

Problem 114

Chapter 1 describes the difference between observations, laws, and theories. Cite one example of a law from this chapter and explain why it is a law.

David Collins

Numerade Educator

01:03

Problem 115

The atomic mass of fluorine is 19.00 amu, and all fluorine atoms in a naturally occurring sample of fluorine have this mass. The atomic mass of chlorine is 35.45 amu, but no chlorine atoms in a naturally occurring sample of chlorine have this mass. Provide an explanation for the difference.

David Collins

Numerade Educator

00:40

Problem 116

The atomic mass of germanium is 72.61 amu. Is it likely that any individual germanium atoms have a mass of 72.61 amu?

David Collins

Numerade Educator

01:42

Problem 117

Copper has only two naturally occurring isotopes, Cu63 and $\mathrm{Cu}-65 .$ The mass of $\mathrm{Cu}-63$ is $62.9396 \mathrm{amu},$ and the mass of $\mathrm{Cu}-65$ is 64.9278 amu. Use the atomic mass of copper to determine the relative abundance of each isotope in a naturally occurring sample.

David Collins

Numerade Educator

01:21

Problem 118

Gallium has only two naturally occurring isotopes, Ga69 and $\mathrm{Ga}-71 .$ The mass of $\mathrm{Ga}-69$ is $68.9256 \mathrm{amu},$ and the mass of Ga-71 is 70.9247 amu. Use the atomic mass of gallium to determine the relative abundance of each isotope in a naturally occurring sample.

David Collins

Numerade Educator

02:49

Problem 119

The figure shown here is a representation of 50 atoms of a fictitious element with the symbol Nt and atomic number $120 .$ Nt has three isotopes represented by the following colors: $\mathrm{Nt}-304$ (red), $\mathrm{Nt}-305$ (blue), and $\mathrm{Nt}-$ 306 (green).(a) Assuming that the figure is statistically representative of naturally occurring $\mathrm{Nt}$, what is the percent natural abundance of each Nt isotope?(b) Use the listed masses of each isotope to calculate the atomic mass of Nt. Then draw a box for the element similar to the boxes for each element shown in the periodic table in the inside front cover of this book. Make sure your box includes the atomic number, symbol, and atomic mass. (Assume that the percentages from part (a) are correct to four significant figures.)

David Collins

Numerade Educator

02:48

Problem 120

Neutron stars are believed to be composed of solid nuclear matter, primarily neutrons.
(a) If the radius of a neutron is $1.0 \times 10^{-13} \mathrm{cm},$ calculate its density in $\mathrm{g} / \mathrm{cm}^{3}$ (volume of a sphere $=\frac{4}{3} \pi r^{3}$ ).
(b) Assuming that a neutron star has the same density as a neutron, calculate the mass in kilograms of a small piece of a neutron star the size of a spherical pebble with a radius of $0.10 \mathrm{mm}$

David Collins

Numerade Educator

02:54

Problem 121

Complete the following table.

Bryan Lynn

Numerade Educator