0654 - P7 - Radioactivity Quiz

A certain element has several isotopes. Which statement about these isotopes is correct?

• They must have the same number of nucleons in their nuclei.
• They must have different numbers of electrons orbiting their nuclei.
• They must have the same number of protons in their nuclei.
• They must have the same number of neutrons in their nuclei.

A very important experiment increased scientists' understanding of the structure of matter. In the experiment, particles scattered as they passed through a thin metal foil. Which particles were used, and to which conclusion did the experiment lead?

• particles = beta particles; conclusion = matter is made up of atoms
• particles = alpha particles; conclusion = atoms have a very small nucleus
• particles = beta particles; conclusion = atoms have a very small nucleus
• particles = alpha particles; conclusion = matter is made up of atoms

Below are four statements about isotopes of a certain element. Which statement about the isotopes must be correct?

• They have the same number of neutrons.
• They are unstable.
• They have the same number of protons.
• They are radioactive.

The scattering of a-particles by a thin metal foil supports the nuclear model of an atom. Why are a-particles used rather than neutrons?

• because they are larger in diameter
• A because they always travel more slowly
• because they are heavier
• because they have a positive charge

The arrangement shown is used to check whether the flour inside a cardboard packet is above a certain level. If it is above this level, the flour absorbs the radiation from the source so that it doesn't reach the detector. Which type of radiation is suitable to use?

• a-particles only
• y-rays only
• either a-particles or B-particles
• B-particles only

A radioactive nucleus contains 128 nucleons. It emits a B-particle. How many nucleons are now in the nucleus?

• 124
• 127
• 128
• 129

Which diagram could represent the structure of a neutral atom?

• A
• B
• C
• D

A reading is taken every 10 minutes of the number of emissions per second from a radioactive source. The table shows the readings. What is the half-life of the source? Select one of the following:

• 40 min
• 10 min
• 60 min
• 20 min

A radioactive decay can be represented as shown. The equation is incomplete. In this decay, the nucleus changes by:

• emitting a ß-particle.
• emitting an a-particle.
• absorbing a proton.
• absorbing a neutron.

The graph shows how the decay rate of a radioactive source changes with time. What will be the decay rate at 8 days?

• 125 decays/s
• 250 decays/s
• 500 decays/s
• 0 decays/s