Physics 9702 · AS & A Level · Atoms, nuclei and radiation

Atoms, nuclei and radiation — practice question

Uranium-238 ($^{238}_{92}\text{U}$) is one of uranium’s isotopes.
(a)[2]

What is meant by isotopes?

(b(i))[1]

For a uranium-238 nucleus, state how many protons it has.

(b(ii))[1]

For a uranium-238 nucleus, state how many neutrons it has.

(c(i))[2]

A uranium-238 nucleus has a radius of $8.9 \times 10^{-15}\,\text{m}$. Calculate, for a uranium-238 nucleus, its mass.

(c(ii))[2]

Calculate, for a uranium-238 nucleus, its mean density.

(d)[2]

A lump of uranium has a density of $1.9 \times 10^{4}\,\text{kg m}^{-3}$. Using your answer to (c)(ii), suggest what can be inferred about the structure of the atom.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: identical proton/atomic number

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