P4 Atomic structure AQA (Combined)

Front

What is the radius of an atom? Options: 1 x 10^-10 m, 1 x 10¹⁰ m, 1/1000 m

Back

1 x 10^-10 m

Answer explanation

The radius of an atom is approximately 1 x 10^-10 m, which reflects the scale of atomic structures. The other options are either too large or not representative of atomic dimensions.

Front

What is the radius of an atom's nucleus?

Back

1/2 of the atom

Answer explanation

The radius of an atom is approximately 1 x 10^-10 m, which reflects the scale of atomic structures. The other options are either too large or not representative of atomic dimensions.

Front

What is an isotope?

Back

An atom of an element with a different number of neutrons

Answer explanation

An isotope is defined as an atom of an element that has a different number of neutrons. This variation in neutrons results in different atomic masses, while the number of protons remains the same, defining the element.

Front

What is an ion?

Back

An atom of an element with a different number of electrons

Answer explanation

An ion is formed when an atom gains or loses electrons, resulting in a net charge. This distinguishes it from isotopes, which have different numbers of neutrons, and different elements, which have different numbers of protons.

Front

Radioactive decay

Back

An unstable nucleus breaks down to become more stable, giving off radiation

Answer explanation

Radioactive decay occurs when an unstable nucleus breaks down to achieve stability, emitting radiation in the process. This makes the first answer choice the most accurate, as it specifically refers to the nucleus.

Front

What is activity?

Back

The rate that nuclei decay

Answer explanation

Activity refers to the rate at which unstable nuclei decay over time, making 'The rate that nuclei decay' the correct choice. The other options incorrectly refer to particles that do not decay in the same context.

Front

What is the unit of activity?

Back

Becquerels (Bq)

Answer explanation

The unit of activity in radioactivity is measured in Becquerels (Bq), which represents one disintegration per second. This distinguishes it from other units like Coulombs, Hertz, and Pascals, which measure different physical quantities.

Front

Count rate

Back

Number of decays per second by a Geiger-Muller tube

Answer explanation

Count rate refers to the number of decays per second detected by a Geiger-Muller tube. This measurement indicates the rate of radioactive decay events, making it the correct choice among the options provided.

Front

What is half life?

Back

The time taken for half of the nuclei in a sample to decay

Answer explanation

Half-life refers to the time required for half of the unstable nuclei in a sample to undergo radioactive decay. Thus, the correct choice is 'The time taken for half of the nuclei in a sample to decay'.

Front

Contamination

Back

Coming into contact with radioactive materials

Answer explanation

Contamination specifically refers to coming into contact with radioactive materials, which can lead to the presence of these harmful substances on surfaces or within the body. Being exposed to nuclear radiation is a separate concern.