Isotopes in Use

Now that you've found the mass of isotopes on your own, let's see how scientists actually look at isotopes!

Isotopes

Isotopes: How are they Measured?

A mass spectrometer is an instrument used to separate an element’s isotopes and to measure the relative isotope abundances.​

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Isotopes: How are they Measured?

How does a spectrometer work?​

Within the spectrometer, beams made of charged atoms (ions) from one element are passed through a strong magnetic field. The ions are selected to have identical charges and velocities.

As the ions pass through the magnetic field, the ion paths are influenced by the magnetic force.

Ions of greater mass possess greater inertia or a greater tendency to continue in a straight line. Ions of lesser mass are more influenced by the field and demonstrate greater deviation. ​

VIDEO TIME!: How does a spectrophotometer work?

Isotopes: How are they Measured?

What does a spectrometer produce?

​Here is an example of a mass spectrometer reading. It displays the result of passing ions of an element through a spectrometer.​

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*​Note the aces

**The Y-axis should say relative percent abundance

Isotopes: How are they Measured?

What does this tell us?

​This element has 1 isotope with a mass of 27.

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Most elements have more than 1 isotope, resulting in more bars on this type of graph.​ An example is next!

​You will need to determine the element then write each isotope in isotope notation.

Isotopes: How are they Measured?

Now you try.

Check it out. Questions coming on the next two slides.

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Identify the element.

Isotope Notation.​

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Fill in the Blanks

Draw

Represent each isotope in proper isotope notation.

Isotopes: How are they Measured?

Another Example.

Check it out. Questions coming on the next two slides.

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Identify the element.

Isotope Notation.​

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Fill in the Blanks

Draw

Represent each isotope in proper isotope notation.

Multiple Select

Select all that is true.

Isotopes of the same atom have...

• the same number of protons.

• the same mass.

• different quantities of neutrons.

• different masses.

Multiple Choice

How many protons does P-30 have?

• 30
• 16
• 12
• 15

Multiple Choice

How many protons does He have?

• 4
• 2
• 6
• 0

Multiple Choice

The top number in this isotope notation is

• the mass number
• the atomic number
• the atomic mass
• the neutron number

Multiple Choice

The bottom number in this isotope notation is

• the mass number
• the atomic number
• the atomic mass
• the neutron number

Multiple Choice

According to the isotopic notation for copper-63, how many neutrons are present in this type of atom?

• 29
• 34
• 63
• 92

Multiple Choice

How many protons does this isotope of titanium have?

• 48
• 22
• 26
• 70