Question 1

What are isotopes?

Accepted Answer

Types of atoms with the same number of protons (the same element) but different numbers of neutrons

Same atomic number & element type; different atomic mass

Question 2

What is relative abundance?

Accepted Answer

The percentage of an isotope with a specific atomic mass found within naturally occurring samples of an element

( has a relative abundance of 98.90%)

Question 3

What is mass spectrometry?

Accepted Answer

A technique to find the relative abundance of an isotope

Question 4

How do mass spectrometers work?

Accepted Answer

Ionizes atoms and molecules with a high-energy electron beam, then deflects the ions through a magnetic field based on their masses

(technically based on their mass-to-charge (m/z) ratio, not mass, but the charge is usually just 1)

Question 5

What is a mass spectrum of a sample?

Accepted Answer

A graph that shows the relative abundance of ions on the y-axis and their atomic mass on the x-axis

(x-axis is technically the mass-to-charge ratio (m/z), but the charge is usually just 1)

Question 6

How do you find the atomic mass from the relative abundances of isotopes?

Accepted Answer

Multiply the atomic mass of each isotope by its relative abundance, then add them all together

(for chlorine: )

Question 7

How do you recognize an element from its mass spectrum?

Accepted Answer

Find its atomic mass, then see which element is closest to that mass on the periodic table

Mass Spectroscopy of Elements, AP Chemistry Flashcards