Skip to main content
Ch.2 - Atoms & Elements
Chapter 2, Problem 72

Sketch the mass spectrum of magnesium given its three naturally occurring isotopes with the following masses and natural abundances: Isotope Mass (amu) Abundance (%) - Mg-24: 23.9850, 78.99% - Mg-25: 24.9858, 10.00% - Mg-26: 25.9826, 11.01%.

Verified step by step guidance
1
Identify the isotopes of magnesium and their respective masses and abundances: Mg-24 (23.9850 amu, 78.99%), Mg-25 (24.9858 amu, 10.00%), Mg-26 (25.9826 amu, 11.01%).
Understand that a mass spectrum displays the relative abundance of each isotope as a function of its mass-to-charge ratio (m/z), which in this case is equivalent to the mass of the isotope since the charge is +1.
On the x-axis of the mass spectrum, plot the mass of each isotope: 23.9850, 24.9858, and 25.9826.
On the y-axis, plot the relative abundance of each isotope. Convert the percentage abundances to a scale where the most abundant isotope (Mg-24) is set to 100. This means Mg-24 will be at 100, Mg-25 at (10.00/78.99)*100, and Mg-26 at (11.01/78.99)*100.
Draw vertical lines (peaks) at each mass value on the x-axis, with the height of each peak corresponding to the relative abundance calculated in the previous step.