A sample of magnesium has the following isotopic composition.

Calculate the relative atomic mass of magnesium based on this data, giving your answer to two decimal places.

Naturally occurring gallium consists of the isotopes ⁷¹Ga and ⁶⁹Ga. What is the approximate percentage abundance of ⁶⁹Ga?

M_r(Ga) = 69.72.

A.  40 %

B.  50 %

C.  60 %

D.  75 %

What is represented by A in ${}_{\text{Z}}^{\text{A}}{\text{X}}^{2-}$?

A. Number of electrons

B. Number of neutrons

C. Number of nucleons

D. Number of protons

The mass spectrum of chlorine is shown.

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Outline the reason for the two peaks at $m/z=35$ and $37$.

Natural uranium needs to be enriched to increase the proportion of ²³⁵U. Suggest a technique that would determine the relative abundances of ²³⁵U and ²³⁸U.

The mass spectrum of chlorine is shown.

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Outline the reason for the two peaks at $m/z=35$ and $37$.

Which representation would be correct for a species, Z, which has 31 protons, 40 neutrons and 28 electrons?

A. ${}_{31}^{71}{\mathrm{Z}}^{3+}$

B. ${}_{31}^{71}{\mathrm{Z}}^{3-}$

C. ${}_{40}^{71}{\mathrm{Z}}^{3+}$

D.  ${}_{28}^{71}{\mathrm{Z}}^{3+}$

Which is correct for ${}_{16}^{34}{\text{S}}^{2-}$?

State the nuclear symbol notation, ${}_{\text{Z}}^{\text{A}}\text{X}$, for iron-54.

What is the relative atomic mass, $A_{\mathrm{r}}$, of an element with this mass spectrum?

A.  $24.0$

B.  $24.3$

C.  $24.9$

D.  $25.0$

State one analytical technique that could be used to determine the ratio of ¹⁴N:¹⁵N.

A sample of gas was enriched to contain 2 % by mass of ¹⁵N with the remainder being ¹⁴N.

Calculate the relative molecular mass of the resulting N₂O.

Describe how the relative atomic mass of a sample of calcium could be determined from its mass spectrum.

State the number of protons, neutrons and electrons in each species.

State one analytical technique that could be used to determine the ratio of ¹⁴N : ¹⁵N.

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

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

Calculate the relative atomic mass, A_r, of this sample of magnesium to two decimal places.

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

Naturally occurring silver is composed of two stable isotopes, ¹⁰⁷Ag and ¹⁰⁹Ag.

The relative atomic mass of silver is 107.87. Show that isotope ¹⁰⁷Ag is more abundant.

What does ${}_{12}^{24}M{g}^{2+}$ represent?

A.     An ion with 12 protons and 24 neutrons

B.     An ion with 14 protons and 24 neutrons

C.     An ion with 12 protons and 12 neutrons

D.     An ion with 12 protons and 22 neutrons

State the nuclear symbol notation, ${}_{\text{Z}}^{\text{A}}\text{X}$, for iron-54.

Mass spectrometry analysis of a sample of iron gave the following results:

Calculate the relative atomic mass, A_r, of this sample of iron to two decimal places.

A sample of gas was enriched to contain 2 % by mass of ¹⁵N with the remainder being ¹⁴N.

Calculate the relative molecular mass of the resulting N₂O.

What is the relative molecular mass of bromine, according to the following mass spectrum?

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.

A.  $\frac{158\times 52+160\times 100+162\times 48}{52+100+48}$

B.  $\frac{158\times 52+160\times 100+162\times 48}{158+160+162}$

C.  $\frac{79\times 11+81\times 11+158\times 52+160\times 100+162\times 48}{11+11+52+100+48}$

D.  $\frac{79\times 11+81\times 11}{11+11}$

Explain the presence and relative abundance of the peak at $m/z=74$.

The stable isotope of rhenium contains 110 neutrons.

State the nuclear symbol notation ${}_{\text{Z}}^{\text{A}}\text{X}$ for this isotope.

What is represented by ^“2−” in ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}^{2-}$?

A.  loss of electron

B.  gain of electron

C.  loss of proton

D.  gain of proton

State the number of protons, neutrons and electrons in each species.

Explain the presence and relative abundance of the peak at $m/z=74$.

Mass spectrometry analysis of a sample of iron gave the following results:

Calculate the relative atomic mass, A_r, of this sample of iron to two decimal places.

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.

Which species has two more neutrons than electrons?

${}_3{}^{6}L{i}^{+}$             ${}_4{}^{9}B{e}^{2+}$             ${}_{11}{}^{23}N{a}^{+}$             ${}_{20}{}^{42}C{a}^{2+}$

A.  ${}_3{}^{6}L{i}^{+}$

B.  ${}_4{}^{9}B{e}^{2+}$

C.  ${}_{11}{}^{23}N{a}^{+}$

D.  ${}_{20}{}^{42}C{a}^{2+}$