Deck 2: Atoms, molecules, and Ions

Question 1

The observation that hydrogen and oxygen can react to form two compounds with different chemical and physical properties,one having an O:H mass ratio = 8:1 and the other having an O:H mass ratio = 16:1 is consistent with the law of

A)definite proportions.
B)energy conservation.
C)mass conservation.
D)multiple proportions.

Answer 1

multiple proportions.

Question 2

The observation that 4.0 g of hydrogen reacts with 32.0 g of oxygen to form a product with
O:H mass ratio = 8:1,and 6.0 g of hydrogen reacts with 48.0 g of oxygen to form the same product
With O/H mass ratio = 8:1 is evidence for the law of

A)definite proportions.
B)energy conservation.
C)mass conservation.
D)multiple proportions.

Answer 2

definite proportions.

Question 3

The existence of electrons in atoms of all elements was demonstrated by

A)Millikan's oil drop experiment.
B)Rutherford's gold foil experiment.
C)Thomson's cathode ray tube experiment.
D)None of these

Answer 3

Thomson's cathode ray tube experiment.

Question 4

Which of the following is a part of Dalton's atomic theory?

A)Atoms are rearranged but not changed during a chemical reaction.
B)Atoms break down during radioactive decay.
C)Atoms contain protons,neutrons,and electrons.
D)Isotopes of the same element have different masses.

Question 5

According to history,the concept that all matter is composed of atoms was first proposed by

A)the Greek philosopher Democritus,but not widely accepted until modern times.
B)Dalton,but not widely accepted until the work of Mendeleev.
C)Dalton,but not widely accepted until the work of Einstein.
D)Dalton,and widely accepted within a few decades.

Question 6

A proton is approximately

A)200 times larger than an electron.
B)2000 times larger than an electron.
C)200 times smaller than an electron.
D)2000 times smaller than an electron.

Question 7

The mass number of an atom is equal to the number of

A)electrons.
B)neutrons.
C)protons.
D)protons plus neutrons.

Question 8

A sample of pure lithium carbonate contains 18.8% lithium by mass.What is the % lithium by mass in a sample of pure lithium carbonate that has twice the mass of the first sample?

A)9)40%
B)18.8%
C)37.6%
D)75.2%

Question 9

The existence of neutrons in the nucleus of an atom was demonstrated by

A)Millikan's oil drop experiment.
B)Rutherford's gold foil experiment.
C)Thomson's cathode ray tube experiment.
D)None of these

Question 10

Methane and oxygen react to form carbon dioxide and water.What mass of water is formed if 3.2 g of methane reacts with 12.8 g of oxygen to produce 8.8 g of carbon dioxide?

A)7)2 g
B)8)8 g
C)14.8 g
D)16.0 g

Question 11

Sodium metal and water react to form hydrogen and sodium hydroxide.If 5.98 g of sodium react with water to form 0.26 g of hydrogen and 10.40 g of sodium hydroxide,what mass of water was consumed in the reaction?

A)4)68 g
B)5)98 g
C)10.14 g
D)10.66 g

Question 12

Most of the alpha particles directed at a thin gold foil in Rutherford's experiment

A)bounced directly back from the foil.
B)passed directly through the foil undeflected.
C)passed through the foil but were deflected at an angle.
D)were absorbed by the foil.

Question 13

Which of the following statements is not a postulate of Dalton's atomic theory?

A)Each element is characterized by the mass of its atoms.
B)Atoms are composed of protons,neutrons,and electrons.
C)Chemical reactions only rearrange atomic combinations.
D)Elements are composed of atoms.

Question 14

The charge-to-mass ratio of an electron was established by

A)Millikan's oil drop experiment.
B)Rutherford's gold foil experiment.
C)Thomson's cathode ray tube experiment.
D)None of these

Question 15

The current model of the atom in which essentially all of an atom's mass is contained in a very small nucleus,whereas most of an atom's volume is due to the space in which the atom's electrons move was established by

A)Millikan's oil drop experiment.
B)Rutherford's gold foil experiment.
C)Thomson's cathode ray tube experiment.
D)None of these

Question 16

Which of the following is not explained by Dalton's atomic theory?

A)conservation of mass during a chemical reaction
B)the existence of more than one isotope of an element
C)the law of definite proportions
D)the law of multiple proportions

Question 17

The symbol that is usually used to represent atomic number is ________.

A)A
B)N
C)X
D)Z

Question 18

Which subatomic particle has the smallest mass?

A)a proton
B)a neutron
C)an electron
D)an alpha particle

Question 19

The observation that 15.0 g of hydrogen reacts with 120.0 g of oxygen to form 135.0 g of water is evidence for the law of

A)definite proportions.
B)energy conservation.
C)mass conservation.
D)multiple proportions.

Question 20

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium.How much calcium is contained in 45.0 g of calcium fluoride?

A)2)56 g
B)7)70 g
C)15.0 g
D)23.1 g

Question 21

The element antimony has an atomic weight of 121.757 amu and only two naturally-occurring isotopes.One isotope has an abundance of 57.3% and an isotopic mass of 120.904 amu.Based on these data,what is the mass of the other isotope?

A)121.757 amu
B)122.393 amu
C)122.610 amu
D)122.902 amu

Question 22

An element has two naturally occurring isotopes.One has an abundance of 37.4% and an isotopic mass of 184.953 amu,and the other has an abundance of 62.6% and a mass of 186.956 amu.What is the atomic weight of the element?

A)185.702 amu
B)185.954 amu
C)186.207 amu
D)186.956 amu

Question 23

The number of atoms of carbon in 12 g of carbon is closest to .

A)12
B)10²²
C)10²³
D)10²⁴

Question 24

The smallest sample of carbon atoms that can be observed with the naked eye has a mass of approximately 2 × 10^-8 g.Given that 1 g = 6.02 × 10²³ amu,and that carbon has an atomic weight of 12.01 amu,determine the number of carbon atoms present in the sample.

A)1 × 10¹⁵
B)1 × 10¹⁶
C)1 × 10¹⁷
D)6 × 10²³

Question 25

What is the chemical symbol for an atom that has 29 protons and 36 neutrons?

A)Cu
B)Kr
C)N
D)Tb

Question 26

One mole of which element has the smallest mass?

A)Co
B)Cu
C)Ni
D)Zn

Question 27

How many protons (p)and neutrons (n)are in an atom of
?

A)38 p,52 n
B)38 p,90 n
C)52 p,38 n
D)90 p,38 n

Question 28

What is the mass of one atom of the element hydrogen?

A)2)0 g
B)1)0 g
C)3)4 × 10^{-24 g}
D)1)7 × 10^{-24 g}

Question 29

How many protons (p)and neutrons (n)are in an atom of calcium-46?

A)20 p,26 n
B)20 p,46 n
C)26 p,20 n
D)46 p,60 n

Question 30

How many protons (p),neutrons (n),and electrons (e)are in one atom of
?

A)12 p,12 n,12 e
B)12 p,11 n,12 e
C)12 p,11 n,10 e
D)12 p,11 n,14 e

Question 31

The atoms of a particular element all have the same number of protons as neutrons.Which of the following must be true?

A)The atomic weight must be a whole number.
B)The mass number for each atom must equal the atomic weight of the element.
C)The mass number must be exactly twice the atomic number for each atom.
D)All of these are true.

Question 32

Which of the following two atoms are isotopes?

A) ^and
B) ^and
C) ^and
D) ^and

Question 33

How many electrons are in a neutral atom of iodine-131?

A)1
B)53
C)54
D)131

Question 34

24.0 g of which element contains the greatest number of atoms?

A)B
B)C
C)N
D)O

Question 35

The isotope represented by
^{is named}

A)carbon-6
B)carbon-7
C)carbon-13
D)carbon-19

Question 36

What is the standard isotope that is used to define the number of atoms in a mole?

A)(¹H)
B)(¹²C)
C)(¹⁶O)
D)(²⁰Ne)

Question 37

Boron-9 can be represented as

A) ^.
B) ^.
C) ^.
D) ^.

Question 38

Which are isotopes? An atom that has an atomic number of 34 and a mass number of 76 is an isotope of an atom that has

A)an atomic number of 32 and a mass number of 76.
B)an atomic number of 34 and a mass number of 80.
C)42 neutrons and 34 protons.
D)42 protons and 34 neutrons.

Question 39

Identify the chemical symbol of element Q in

A)Br
B)Hg
C)Pd
D)Se

Question 40

Which of the following represent isotopes?
[A: ]
[ B: ]
[ C: ]
[ D: ]

A)A and B
B)A and C
C)A and D
D)C and D

Question 41

The number of neutrons in
Is

A)26.
B)29.
C)53.
D)55.

Question 42

Positron emission changes the atomic number of an element by

A)-2.
B)-1.
C)+1.
D)+2.

Question 43

Which of the following statements about gamma radiation is false?

A)It almost always accompanies alpha or beta emission.
B)It is a mechanism to release excess energy in the nucleus.
C)Gamma rays are high energy photons.
D)The mass number decreases by one with each gamma emitted.

Question 44

The number of nucleons in an atom or ion is the same as the

A)atomic number.
B)charge on the atom or ion.
C)mass number.
D)none of these

Question 45

Which of the following statements is not correct when balancing a nuclear equation?
I.The mass numbers must be conserved on both sides of the reaction arrow.
II.The ionic charges must be conserved on both sides of the reaction arrow.
III.The atomic numbers must be conserved on both sides of the reaction arrow.
IV.The elements must be the same on both sides of the reaction arrow.

A)II only
B)II and III
C)I and III
D)II and IV

Question 46

The number of nucleons in a
nucleus is

A)92.
B)144.
C)236.
D)328.

Question 47

A beta particle is

A) .
B) .
C) .
D) .

Question 48

A positron is

A) .
B) .
C) .
D) .

Question 49

Which statement about nuclear reactions is true?

A)New elements are never produced in a nuclear reaction.
B)Nuclear reactions involve valence electrons.
C)The rate of a nuclear reaction is affected by catalysts.
D)Tremendous amounts of energy are involved in nuclear reactions.

Question 50

Gamma radiation can be described as

A)a helium nucleus.
B)a negatively charged free electron.
C)high energy electromagnetic radiation.
D)a positively charged free electron.

Question 51

The rate of a nuclear reaction can be changed by

A)adding a catalyst.
B)decreasing the pressure.
C)increasing the temperature.
D)None of these

Question 52

The nuclear decay process that involves the particle having the greatest mass is ________ emission.

A)alpha
B)beta
C)gamma
D)positron

Question 53

"Isotopes" are atoms with the same number of ________ but different number of ________.

A)electrons,protons
B)neutrons,protons
C)protons,electrons
D)protons,neutrons

Question 54

When a substance decays by alpha radiation,the mass number of the nucleus ________ and the atomic number ________.

A)increases by 4,increases by 2
B)reduces by 4,reduces by 2
C)increases by 2,increases by 4
D)reduces by 2,reduces by 4

Question 55

Beta decay of ²⁴Na produces a beta particle and

A)(²⁰F.)
B)(²³Na.)
C)(²⁴Ne.)
D)(²⁴Mg.)

Question 56

When a substance decays by beta emission,the mass number of the nucleus ________ and the atomic number ________.

A)decreases by 1,remains the same
B)increases by 1,remains the same
C)remains the same,decreases by 1
D)remains the same,increases by 1

Question 57

An alpha particle is

A) .
B) .
C) .
D) .

Question 58

How many moles and how many atoms of zinc are in a sample weighing 34.9 g?

A)0)533 mol,8.85 ×10^-25 atoms
B)0)533 mol,3.21 ×10²³ atoms
C)1)87 mol,3.10 × 10^-24 atoms
D)1)87 mol,1.13 × 10²⁴ atoms

Question 59

Which of the following statements about positrons is false?

A)The positron has same mass as an electron.
B)A positron is ejected from the nucleus during the conversion of a proton into a neutron.
C)A positron is a positive electron.
D)When positron emission occurs,the atomic number of the nucleus increases.

Question 60

The term "nucleons" refers to the number of ________ in the atom.

A)neutrons
B)protons
C)protons and neutrons
D)protons,neutrons,and electrons

Question 61

Which is the only element that contains more protons than neutrons in its most abundant stable isotope?

A)boron
B)carbon
C)hydrogen
D)mercury

Question 62

Which one of the following combinations of neutrons/protons results in the lowest number of nonradioactive (stable)isotopes?

A)even number protons/even number neutrons
B)even number protons/odd number neutrons
C)odd number protons/even number neutrons
D)odd number protons/odd number neutrons

Question 63

Which one of the following processes does not result in transmutation to another element?

A)alpha emission
B)beta emission
C)electron capture
D)gamma emission

Question 64

Which of the following elements would you expect to have the largest number of stable isotopes? Element number:

A)48
B)49
C)50
D)51

Question 65

In addition to a beta particle,what is the other product of beta decay of
?

A)
B)
C)
D)

Question 66

Which of the following statements about electron capture is false?

A)The electron is used to convert a proton to a neutron.
B)The electron involved is most likely an outer shell valence electron.
C)In electron capture decay,the atomic number decreases by one.
D)In electron capture decay,the mass number remains unchanged.

Question 67

Tritium, ,is formed in the upper atmosphere when Captures a neutron and then decays.What is the other product of this reaction?

A)
B)
C)
D)

Question 68

When more than 3000 known nuclides are plotted on a neutron/proton grid they make up a group called

A)the "island of stability."
B)the "peninsula of nuclear stability."
C)the "sea of instability."
D)none of these

Question 69

A radioisotope which is neutron poor and very heavy is most likely to decay by

A)alpha emission,electron capture,or positron emission.
B)only alpha emission.
C)only electron capture.
D)only positron emission.

Question 70

Which reaction below represents Decay by electron capture?

A) + →
B) + →
C) + →
D) + →

Question 71

Which one of the following statements about isotopes is false?

A)The ratio of neutrons to protons is about 1:1 for elements lighter than Ca.
B)The ratio of neutrons to protons is > 1:1 for elements heavier than Ca.
C)Nonradioactive isotopes generally have an odd number of neutrons.
D)All isotopes beyond ²⁰⁹Bi are radioactive.

Question 72

Which reaction below represents Decay by alpha emission?

A) → +
B) → +
C) → p +
D) → n +

Question 73

Which process decreases the neutron/proton ratio?

A)alpha emission
B)beta emission
C)electron capture
D)positron emission

Question 74

Which reaction below represents Decay by positron emission?

A) → +
B) → +
C) → +
D) → +

Question 75

The nuclear transformation potassium-40 argon-40 + ? is classified as

A)alpha emission.
B)beta emission.
C)electron capture.
D)positron emission.

Question 76

Which of the following nuclides is most likely to undergo beta decay?

A)
B)
C)
D)

Question 77

As the atomic number of the elements increases,the ratio of neutrons to protons in stable nuclei

A)decreases.
B)stays the same.
C)increases.
D)is unrelated to stability.

Question 78

Which of the following decay processes give a product nuclide whose atomic number is one less than the starting nuclide?

A)alpha decay
B)beta decay and positron decay
C)gamma decay and beta decay
D)positron decay and electron capture

Question 79

Which of the following elements would be expected to be particularly stable?

A)
B)
C)
D)

Question 80

A radioisotope has a neutron/proton ratio which is too low.Which of the following processes will not occur for such a nucleus?

A)alpha emission
B)beta emission
C)electron capture
D)positron emission