PHY 102-Chapters 8, 9, 11, & 12 Review

You start out with 1000 atoms of a radioactive substance. After 3522 years, you have 250 atoms of the substance. What is the half-life of the radioactive substance in years? Round your answer to the nearest whole number.

1761

A radioactive source has a half-life of 3 minutes. At t=0, it is placed near a geiger counter and the count rate is 3000 counts/sec. What is the count rate at t=12 minutes? Round your answer to 1 decimal place.

187.5

How many electrons are in the outermost shell of magnesium?

2

The orbital radius of the 3rd excited state of an atom is 25. 8 angstroms. What is the orbital radius of orbit number 4 in angstroms? Round your answer to 1 decimal place.

25.8

How many protons are in a Boron atom?

5

Approximately how many neutrons are in Ag-108?

61

A radioactive nucleus with atomic number 63 decays by emitting an electron. What is the nucleus's atomic number after it decays?

64

How many electrons are in the outermost shell of chlorine?

7

How many electrons are in a neutral oxygen atom?

8

An element will decay to an element with higher atomic number in the periodic table if it emits A. a beta particle B. a gamma ray C. a proton D. an alpha particle E. none of these

A. a beta particle

In the periodic table, elements in the same ___ have very similar properties. A. column B. row C. nucleus D. ion E. color

A. column

Different isotopes of an element have different numbers of ___

neutrons

The rate of radioactive decay is proportional to the _____

number of nuclei

An electron in the ground state of an atom has an energy of -55.9 eV. What is the energy of the third excited state? Give your answer in eV, and round to 1 decimal place.

-3.5

The half-life of phosphorus-32 is approximately 14 days. If you have 9.7 grams of phosphorus-32 today, how many grams will be left after 42 days? Round your answer to 1 decimal place.

1.2

Rutherford performed an experiment in which alpha particles were shot at thin gold foil. About how many of the alpa particles bounced backward from the gold foil?

1/1000

A gram of radioactive material has a half-life of one year. After 4 years, how much radioactive material will be left?

1/16 g

Your friend tells you that she has discovered a new element with atomic number 156. How many electrons are in the new element?

156

The half-life of carbon-14 is 5730 years. If a 1-gram sample of old carbon is 1/8 as radioactive as 1-gram of a current sample, then the age of the old sample is about ___

17,200 years

A particular atom has an atomic number of 13. How many electrons are in its 3rd shell?

3

A particular atom has an atomic number of 6. How many electrons are in its 2nd shell?

4

The ground state of energy of an electron in an atom is -51.1 eV. When an electron transitions from orbit number 3 to the ground state, how much energy is given off? Round to 1 decimal place.

45.4

The ground state energy of an electron in an atom is -68.5 eV. When an electron transitions from orbit number 3 to the ground state, how much energy is given off? Round to 1 decimal place.

60.9 eV

A certain radioactive isotope placed near a Geiger counter registers 120 counts per minute. If the half-life of the isotope is one day, what will the count rate be at the end for four days?

7.5 counts/min.

A particular nucleus has an atomic number of 16 and an atomic mass of 94 amu. How many neutrons are in the nucleus?

78

When U-238 emits an alpha particle,the nucleus left behind has ___ protons

90

When thorium (atomic number=90) emits a beta particle, the resulting nucleus has atomic number

91

When radium (atomic number=88) emits an alpha particle, the resulting nucleus has atomic number A. 86 B. 88 C. 90 D. 92 E. none of these

A. 86

When a nucleus emits a beta particle, its atomic number A. increases by 1. B. decreases by 1. C. increases by 2. D. decreases by 2. E. none of these

A. increases by 1

Compared to the mass of a uranium nucleus before splitting, the pieces it splits into have A. less mass B. the same mass. C. more mass.

A. less mass

The Bohr model of the atom is akin to a A. miniature solar system B. blob of plum pudding, where raisins represent atomic nuclei C. central heavy ball with lighter balls connected by springs D. all of these

A. miniature solar system

There is a greater proportion of carbon 14 in A. new bones B. old bones C. same in each

A. new bones

Nuclei which are all isotopes of an element all have the same A. number of protons B. mass C. number of nucleons D. number of neutrons

A. number of protons

Carbon dating requires that the object being tested contain A. organic material B. inorganic material C. charcoal D. sugar molecules E. none of these

A. organic material

What makes an element distinct? A. the number of protons B. the number of neutrons C. the number of electrons D. the total mass of all the particles E. none of these

A. the number of protons

The periodic table is ordered by A. atomic mass B. atomic number C. neutron number D. color of element E. year of element's discovery

B. atomic number

If an alpha particle and a beta particle have the same energy, which particle will penetrate farther into an object? A. alpha particle B. beta particle C. They both penetrate the same distance D. It depends on what atom they decayed from

B. beta particle

What do electrons have that protons always have in equal magnitude? A. mass B. charge C. energy D. all of these E. none of these

B. charge

What is the most recent major nuclear reactor accident? A. Three mile island. B. Chernobyl C. Fukushima D. Braidwood

C. Fukushima

What was Marie Curie's native country? A. France B. Germany C. Poland D. Russia E. America

C. Poland

Most alpha particle fired at a gold foil pass through undeflected because the A. electric field is zero inside the gold B. gold atoms, unlike most other metal atoms, are relatively far apart C. atoms of gold, like an others, are mostly empty space D. net charge of the gold atoms is zero E. none of these

C. atoms of gold, like any others, are mostly empty space

A sphere of pure U-235 will explode if it is A. hot enough B. shaken hard enough C. big enough D. small enough

C. big enough

When an alpha particle is ejected from a nucleus, the nucleus then has less A. mass B. charge C. both of these D. neither of these

C. both of these

In the fissioning of uranium, a chain reaction is caused by A. the enormous energy release B. the kinetic energy of the decay products. C. ejected neutrons. D. the conversion of mass to energy. D. none of these

C. ejected neutrons

What type of radiation is most dangerous to human? A. alpha B. beta C. gamma D. neutron

C. gamma

Which radiation has no electric charge associated with it? A. alpha rays B. beta rays C. gamma rays D. all of these E. none of these

C. gamma rays

Uranium-235, Uranium-238 and Uranium-239 are different A. elements B. ions C. isotopes d. none of these

C. isotopes

An excited atom with lots of states is capable of emitting radiation of A. a single frequency. B. 3 frequencies. C. many more than 3 frequencies.

C. many more than 3 frequenceis

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number A. neutrons B. quarks C. orbital electrons D. all of these E. none of these

C. orbital electrons

A certain radioactive isotope placed near a Geiger counter register 160 counts per second. Eight hours later, the counter registers 10 counts per second. What is the half-life of the isotope? A. 8 hours B. 6 hours C. 4 hours D. 2 hours E. none of these

D. 2 hours

A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. Eight hours later, the counter registers 10 counts per second. What is the half-life of the isotope? A. 8 hours B. 6 hours C. 4 hours D. 2 hours

D. 2 hours

How many protons are in a neutral, stable nitrogen atom? A. 1 B. 2 C. 5 D. 7 E. 14

D. 7

A chain reaction grows when the average number of liberated neutrons that go on to cause further fissions is A. zero B. less than one C. one D. greater than one

D. greater than one

The atomic number is the number of __ in an atom. A. protons B. electrons C. neutrons D. protons or electrons E. protons or neutrons

D. protons or electrons

Who was the scientist to first create the periodic table?

Dmitri Mendeleev

Alpha particles are repelled by atomic nuclei because: A. of the the electric force between an alpha particle and the atomic nucleus. B. closeness of each to each other is not permitted. C. the force between the alpha particle and the atomic nucleus is opposite to an attractive force. D. they both have the same sign of electric charge. E. All of these

E. All of these

When an electron transitions from the 2nd excited state to the first excited state, it gives off A. an atom B. a neutron C. a proton D. an electron E. a photon

E. a photon

J.J. Thomson's model of the atom A. had electrons embedded in some kind of fluid that contained most of the mass of the atom. B. held that the fluid containing most of the mass of the atom had enough positive charge to make the atom electrically neutral. C. failed to predict the observed frequencies of the atom. D. depended upon electric forces to produce stability E. All of the above

E. all of the above

The mass of a nucleus is exactly equal to the sum of the masses of its individual A. separated protons B. separated neutrons C. separated electrons D. all of these E. none of these

E. none of these

The nucleus with the greatest mass is A. hydrogen B. iron C. lead D. uranium E. plutonium

E. plutonium

True or False: If half of a radioactive substance decays in the first 10 s, the other half will decay in the next 10s.

False

True or False: In the Bohr model of the atom, electrons can orbit the nucleus with any radius.

False

True or False: The spectrum of a hydrogen atom is the same as the spectrum of a helium atom.

False

A device that is used primarily to detect nuclear radiation is a

Geiger counter

What was the main problem with J.J. Thomson's plum pudding model of the atom?

It couldn't reproduce experimental data

Something that is not an application of radioactivity.

Steel manufacturing

True or False: If a 20 kg brick is made entirely of radioactive atoms of half-life 5 days, at the end of 5 days this brick will have a mass of 10 kg.

True

True or False: When an electron transitions from the first excited state to the ground state it gives off energy.

True

The half-life on an isotope is one day. At the end of three days, how much of the isotope remains?

one-eighth

The half-life of an isotope is one day. At the end of two days the amount that remains is ___

one-quarter

The atomic number of an element is the same as the number of its

protons