IB Chemistry HL 1.2 The Nuclear Atom Questions

Practise IB Chemistry HL 1.2 with evidence-led questions on atomic structure, isotopes, nuclei and mass spectrometry.

Exam points

Use nuclear symbols to determine proton, neutron and electron counts for atoms and ions.
Distinguish isotopes and interpret abundance or mass-spectrometry data to identify nuclides.
Interpret mass spectra to compare isotopic patterns, relative abundance and molecular or fragment masses.

[Maximum number: 3]

Titanium and vanadium are consecutive elements in the first transition metal series.

(a)

Titanium exists as several isotopes. The mass spectrum of a sample of titanium gave the following data:

Calculate the relative atomic mass of titanium to two decimal places.

[ 2 ]

$\frac{(46\times7.98)+(47\times7.32)+(48\times73.99)+(49\times5.46)+(50\times5.25)}{100} =47.93$

Answer must have two decimal places with a value from 47.90 to 48.00.

(b)

State the number of protons, neutrons and electrons in the ${ }_{22}^{48} \mathrm{Ti}$ atom.

Protons:

......

Neutrons:

......

Electrons:

......

[ 1 ]

[Maximum number: 3]

Magnesium is a group 2 metal which exists as a number of isotopes and forms many compounds.

(a)

State the nuclear symbol notation, ${ }_{Z}^{A} X$ , for magnesium-26.

[ 1 ]

${ }_{12}^{26} \mathrm{Mg}$

(b)

Mass spectroscopic analysis of a sample of magnesium gave the following results:

Calculate the relative atomic mass, $A_{\mathrm{r}}$ , of this sample of magnesium to two decimal places.

[ 2 ]

$A_r=\frac{24(78.60)+25(10.11)+26(11.29)}{100} =24.3269 =24.33$

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