CH. 10 Env. Sci.

The mass of an atomic nucleon is nearly

2000 times the mass of an electron.

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 of four days?

7.5 counts/min

An atom with an imbalance of electrons to protons is

an ion.

The most harmful radiations are those that

damage living cells

A nucleon has more mass when it is

outside the nucleus

The difference in the mass of a nucleon when outside an atomic nucleus compared to inside the nucleus depends on

the atomic number of the nucleus

If an alpha particle and a beta particle have the same energy, which particle will penetrate the farthest in an object?

the beta particle

The mass of a nucleon is greatest where its potential energy is

the greatest

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

90 protons.

When U-235 undergoes fission, the two nuclei that result have a total of

92 protons.

When U-239 emits a beta particle, the nucleus left behind ha

93 protons.

Which of the following isotopes is radioactive?

carbon-14

The most abundant element in the universe is

Hydrogen

It's impossible for a hydrogen atom to emit an alpha particle.

True

Three isotopes that undergo nuclear fission are

U-233, U-235, and Pu-239.

An element will decay to an element with higher atomic number in the periodic table if it emits

a beta particle

An element will decay to an element with higher atomic number in the periodic table if it emits Correct Answer

a beta particle.

Which experiences the least electrical force in an electric field?

a gamma ray

Fissioning an iron nucleus yields a net

absorption of energy

Fissioning helium would yield a net

absorption of energy.

Which experiences the greatest electrical force in an electric field

an alpha particle

In the fissioning of uranium, a chain reaction is caused by

ejected neutrons.

Once an alpha particle is outside the nucleus it is

electrostatically repelled

If gold were used as nuclear fuel, it would be best

fissioned.

if carbon were used as nuclear fuel, it would be best

fused.

Electrical forces inside a nucleus contribute nuclear

instability

Compared to the mass of a uranium nucleus before splitting, the pieces it splits into have

less mass

The amount of radiation we personally encounter that originates in the Earth's and the atmosphere's natural background is

more than half

Different isotopes of an element have different numbers of

neutrons.

A nucleon has more potential energy with respect to a nucleus when it is

outside the nucleus.

The nucleus with the greatest mass is

plutonium.

The nucleus with the most tightly bound nucleons is

plutonium.

Detonation of a fission type atomic bomb is started by

pressing together several small pieces of uranium.

Electric forces within an atomic nucleus tend to

push it apart.

Artificially induced radioactive elements generally have

short half lives.

When uranium emits a beta particle, the result is

transuranic element

A sample of relatively active radioactive material is somewhat

warmer than the environment.

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

1/8

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?

2 hours

A Geiger counter placed 1 m from a point source of radiation registers 100 counts per second. If the Geiger counter is moved closer to 0.5 m from the source, what will the count rate be?

400 counts/min

In nuclear fission and nuclear fusion reactions, the amount of mass converted to energy is about

less than one percent

Compared to the sum of the masses of all the individual nucleons in their separate states that make up a nucleus, the mass of the composite nucleus is

less.

In gaseous form, at the same temperature, the average speed of U-238 compared to the speed of U-235 is

less.

When a gamma ray is emitted by a nucleus, the nucleus then has appreciably less

neither A nor B

There is a greater proportion of carbon-14 in

new bones

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

none of the above

The mass of a nucleus is exactly equal to the sum of the masses of its individual

none of the above

In order for an atom to decay to an element which is one greater in atomic number, it can emit

all of the above

When uranium-238 absorbs a neutron, it

becomes a beta emitter

Hydrogen is a first-rate fuel for

both A and B

In which of these processes is an element of matter changed into a completely different element?

both A and B

The helium in a child's balloon is composed of

both A and B

When an alpha particle is ejected from a nucleus, the nucleus then has less

both A and B

The reason plutonium is not found in any appreciable amounts in natural ore deposits is beca

has a short half-life

When a lump of uranium is broken into smaller pieces, the total surface area of the lump

increases

In both fission and fusion, mass

is changed to the form of kinetic energy.

All deposits of natural uranium contain appreciable amounts of

lead

In a mass spectrometer, a variety of singly-ionized atomic nuclei are directed into a magnetic field where they are deflected and strike a detecting screen. The particles to undergo the greatest deflection are the particles with the

least mass.

If iron were used as nuclear fuel, it would be best

neither A nor B

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

one-quarter.

Plutonium is chemically toxic when it is

oxidized or non-oxidized

Fissioning a lead nucleus yields a net

release energy

An element emits one alpha particle, one positron, and three beta particles. Its atomic number

stays the same

The half-lives of elements beyond uranium are too short for these elements to occur in natural deposits. But elements below uranium that have equally short half-lives do occur in natural deposits. This is because they are

the products of uranium decay

Which will leak more neutrons, two separate lumps of uranium, or the same two lumps stuck together?

two separate lumps

When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number

86.

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

none of the above

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

nucleons