Physics 5054 · O Level · The nuclear model of the atom

The nuclear model of the atom — practice question

Lithium occurs in more than one isotope. Fig. 8.1 shows a neutral atom of a radioactive lithium isotope (Li). The nucleus is surrounded by three electrons in orbits. The nuclide symbols for lithium isotopes are written as $^{X}_{Y}\mathrm{Li}$, where X and Y are numbers.
(a(i))[1]

State one similarity in the compositions of the atoms of all lithium isotopes.

(a(ii))[1]

State one way in which the composition of a lithium atom from one isotope differs from the composition of a lithium atom from another isotope.

(b(i))[2]

Using Fig. 8.1, determine the values of X and Y for the isotope shown.

(b(ii))[1]

An ion of this lithium isotope carries a single positive charge and is written as $(^{X}_{Y}\mathrm{Li}^{+})$. Describe how the diagram representing this ion is different from Fig. 8.1.

(c(i))[1]

Radioactive isotopes give out nuclear radiation that can have effects on living organisms. State one damaging effect of nuclear radiation.

(c(ii))[2]

The release of radioactive radiation from an unstable isotope is said to be random and spontaneous. State what is meant by ‘random’ and what is meant by ‘spontaneous’.

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