1.2 Mass Spectroscopy of Elements

Question 1

What is average atomic mass?

Answer 1

The average atomic mass of an element is the weighted average of the masses of the naturally occurring isotopes of that element, based on their relative abundances.

Question 2

What is an isotope?

Answer 2

Isotopes are variants of an element. They have the same number of protons and electrons but a different number of neutrons.

Question 3

What are carbon’s naturally occurring isotopes?

Answer 3

There are three naturally occuring isoptopes of carbon: carbon-12, carbon-13, and carbon-14

Question 4

Carbon-12

Answer 4

Carbon-12 is the most abundant isotope of carbon. It makes up about 98.9% of naturally occurring carbon. It has an atomic mass of 12 amu and is stable.

Question 5

Carbon-13

Answer 5

Carbon-13 is a less abundant isotope of carbon. It makes up about 1.1% of naturally occurring carbon. It has an atomic mass of 13 amu and is stable.

Question 6

Carbon-14

Answer 6

Carbon=14 is a rare isotope of carbon. It makes up about 1 part per trillion of naturally occurring carbon. It has an atomic mass of 14 amu and is radioactive.

Question 7

How do we calculate average atomic mass?

Answer 7

AAM + (abundance of isotope 1 x mass of isotope 1) + (abundance of isotope 2 x mass of isotope 2) + … +

Question 8

What is mass spectroscopy?

Answer 8

Mass spectroscopy is a technique used to measure the mass and relative abundance of ions. It produces a graph called the mass spectrum.

Question 9

Mass Spectrum

Answer 9

The mass spectrum allows us to identify different isotopes of an element and the relative abundance of each isotope in nature.